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Having subjected “Lo Conpasso De Navegare” (LCN) to an in depth examination within a previous text and shown that it is probably, in the “Starea” or coastal section, unfit for purpose. Thus as it contains a multitude of inaccuracies, I have decided to commence this examination of the Carta Pisane with an explanation of why the draughtsmanship of the chart using that part of LCN is impractical. I suggest that the text ChLCN/1 is first studied!
This whole examination of the chart necessitates explaining the scale used, it is basically 1:4,500,000. Then, its internal structure, the two wind roses and the four peculiar square based measurement units set on the chart. It is then necessary to explain the Peleio distances which are shown to be used to construct the backbone or matrix for the chart itself and its overall draughtsmanship.
However to dispel any thoughts that may exist that the Carta Pisane through its visual presentation of the form of the Mediterranean Sea basin and the parts thereof is the result of an accurate base plot, I will secondly carry out a detailed examination of one section of the chart (just an example) to explain how it was drawn thus obviating large tracts of text later during the in-depth examination.
Why? Simply put; if you understand the intricacies of the draughtsmanship required then the methodology which is exposed will enable a follow through to understand the original cartographic draughtsman’s processes of thought and deed.


There is inadequate information within the LCN to ensure that a cartographer can visualize and then draw the coastline of the Mediterranean Sea basin as my previous text fully illustates. Therefore it is necessary to hypothesize on the possible explanations for a coastline having been drawn with some detail. Firstly, did the cartographer have a text, certainly not LCN, which explained the form of that coastline? Secondly, did the cartographer through his possible sailing experiences know the shape of many parts of the coastline and therefore guessed the residual parts? Thirdly, did the cartographer have numerous small sketches of parts of the coastline, which had scale bars or distance measures attached and hence he was able to transfer them onto his chosen scale plot and infill with the textual information in the first premise?
Thus later in this text the possible original map and data available are discussed.


I have produced a basic diagram explaining the scale bars and thus the setting out of the chart. The two scale bars are set in unusual features, an ellipse, and have notional 50, 100 and 200 millara divisions with the 100 unit being subdivided into 20 parts of 5 millara, although the northern scale bar is slightly awry as indicated on the diagram.
The scale bar length for 100 millara is c27.33mm and thus I can illustrate quite simply the impracticality of using the “Starea” distances from LCN to draw the chart. Many distances are given as 5, 10, 15 and 20 millara set to a compass direction. But consider the draughtsmanship now required to draw those distances on the chart to a given angle.
The millara measurements on the chart would be as follows:
5 mill = 1.37mm: 10 mill = 2.73mm: 15 mill = 4.1mm: 20 mill = 5.47mm: 25 mill = 6.83mm 30 mill = 8.2mm: 40 mill = 10.93mm: 50 mill = 13.67mm and 100 mill = 27.33mm.


Now imagine you are drawing the coastline of the Carta Pisane from LCN data. I have chosen to illustrate the methodology using the LCN text from Capo De Menerba folio 17r to Lo Monte Sancto Angelo folio 21v, which covers the Foot of Italy, one of the iconic Mediterranean Sea features from its geographical form.
Thus we read in LCN;
a) Da Scalea a Sancto Noceto XX millara; garbino meczodi
b) Da Sancta Noceto a l’Amantea VIII millara; meczo – garbino
c) De l’Amantea al capo de Suari ch’e capo de golfo sancta ‘Femia de ponente VII millara per meczodi.
d) Del dicto capo de Suari a Bibona XX millara; meczo – sirocco
e) De Bibona a Turpia V millara; meczodi.
The measurements you would use to draw the above are as follows;
a = 5.47mm; b = 2.19mm; c = 1.92mm; d = 5.47mm and e = 1.37mm.

However, that example does not explain the actuality of drawing the complete Foot of Italy and thus by moving slightly down the coast to the Toe facing Sicily we read;
f) de la dicta Coda de Volpe a la Cotona vellia X millara per sirocco ver lo meczo di.
g) de la Catuna a Rezo X millara per quella starea.
h) de Rezo a pPellari XV millara per quella starea.
i) Dell Pellari a l’Armo V millara per sirocco.
It takes little imagination to understand the consequential enormity of drawing of a chart from items g) and h), “sail by the coastline”; but how do you draw it?
Firstly we must realise the impracticality of drawing the individual “Starea” distances particularly with their given directions in any meaningful way, probably up to and including 25 millara, 6.83mm. This is for information …… as the length of the 6 dots shown is 6.83mm and thus an example of the possible accuracy given the tools available in this era.
Secondly, therefore, the most likely scenario is that some distances were aggregated and marked upon the chart with the coastline infill via freehand sketches approximating to the “Portolani text”. Can that be shown to be a plausible explanation; is the Carta Pisane a contrived chart basically made up from a freehand sketch of coastal sections joining known points? If we return to our example from folios 17v to 21r that hypothesis can be easily indicated as a correct.


There are 64 sections of text which describe the “starea” or coastline from capo de Menerba to Lo Monte Sancto Angelo. If a comparison is made between the Carta Pisane and a geographical plot of the same area the immediate errors on the west coast are evidenced, particularly from Scalea to Bibona where the coastline is suddenly noted from Meczo/Sirocco to Garbino/Meczo and then Meczo/Garbino; a complete reversal by 90 degrees as the diagram illustrates. The distances are also corrupt with Scalea to Amantea geographically 77km or 63 millara, but only 28 millara using LCN.
But if we concentrate on the section from Cape Spartivento to Cape Leoche (Cape Santa Maria de Leuca) the methodology becomes apparent.

Diagrams ChCPS/1/D03

Firstly from LCN; de spartivento – capo Stillone C millara – greco/tramontana.
The chart as drawn has 60 millara and the toponym for Armi is written after Cape Spartivento, not in its geographical position before the cape. The geographical distance is actually 50 millara.
Thus we must recognize that scribal errors abound in the text, particularly the transposition of the “C” and “L” for 100 and 50 millara. In this instance I consider it acceptable to alter the Cape Spartivento to Cape Stillone distance on my plots to 50M.
But following the LCN description further for the map plot, both the Carta Pisane and the Geographical plot illustrate complete non compliance, and thus it is open to opine freehand infill between points or capes. If it is by “Starea” concordance should evidence.
The defining distance for the Foot of Italy is from Cape Spartivento to Cape Santa Maria de Leuca, geographically 280km or 228 millara, but is shown as 260 millara on the Carta Pisane and thus the problem mentioned by other researchers of the over width of Italy (shown by the 32 millara extra) is explained. However the direction of the alignment as drawn is Greco 1/3 Tramontana that is N30E, where geographically it is Greco or N45E, and thus a one third wind deviation. But, draw the LCN plot un-amended onto the Carta Pisane and that dichotomy is resolved. The Carta Pisane with the N30E angle for the Foot of Italy at first does not appear to accord with the LCN plot. However, twist the Carta Pisane to align Cape Spartivento to Cape Leuca at 45 degrees or Greco and the LCN text is perhaps a more likely basis. Returning to the amended plot and the sailing instructions, if the mariner followed the coastline, “starea”, in all probability it would be considered a reasonable guide.
Thus it is open to opine that corrupt as it is the LCN in its original format (not a copy) could have been a useful aid to Mariners sailing the Mediterranean Sea basin. But as a tool to draw a Portolan chart from its “Starea” information it is questionable as to the practicality.



Although there are two diagrams illustrated, the first is for continuity of research being from a previous text concerning the Carta Pisane. The second diagram is an explanation of the setting out via millara measurements of the two wind roses and the four overpowering square and diagonal features. Using the scale bars it is a simple exercise to determine the measurements utilized to draw both features. The basic measurement is 71 millara which is the same unit as used in the “Tavola De Marteloio” for 45 degrees as the first diagram illustrated. But the main circles are set 710 millara radius which is not a 92 divisor and thus the wind rose construction is as described in my text ChWr/1/ChWr/2, and are a geometric form. This is all the more credible when the errors in draughtsmanship of the Carta Pisane are fully observed.
However, this does not explain the overpowering four square/diagonal features set on the chart. One would have been sufficient to provide the user with the 71/100 millara measurements for the charts usage. But, I opine later in this text why I consider there are four features drawn so overpoweringly on the chart.



By drawing the putative geographical graticule, the shape and form of the Carta Pisane can be visualized. It also provides a methodology to better understand the vagaries of the draughtsmanship process. Hence if distance and direction are the arbiters of the actual map, then variations in those, their accuracy in other words, can be readily observed. Commencing at the Pillars, the latitudes/longitudes are set reasonably to the wind rose north but further east around Corsica/Sardinia the longitudes are North/South with latitudes wavering. Thus the longitudinal lines can be seen to be basically north/south across the whole chart. The Latitudinal lines waver and can be explained by the Peleio measurements.
As would be expected a calculation of the latitude/longitude ratio provides a figure close to the 36N ratio of 5:4, which of course derives purely from the distance measures utilised, thus the accuracy is perhaps shown for Peleio distances.








Diagram ChCPS/1/D12

Firstly an objective discussion is required to establish what may be considered accuracy from the chart measures. And here we are met by a dilemma; do we accept 10, 15, 20 or 25 millara difference as accurate given the scale of the Carta Pisane is 1:4,500.000. Although I am using a copy of the Carta Pisane scale 1:3,325,000, which has 37mm for 100 millara that still only produces distances as follows; 5 mill = 1.85mm; 10 mill = 3.7mm; 15 mill = 5.55mm, 20 mill = 7.4mm and 25 mill = 9.25mm. I suggest these are still small measurements to work with and a single marker made with a stylus before drawing the map plot on the Carta Pisane would account for variations up to 10 millara that is 4.1mm on the chart. I accept I am being rather precise in my text but that is reality.

Diagram ChCPS/1/D13

Thus by studying the diagrams attached and reading the information there-on which compares the two as noted and also now includes the geographical distances involved, the accuracy can be fairly established. I have chosen 40 different Peleio distances, quite randomly to assess the western Mediterranean Sea area from the Pillars to Sicily prior to investigating the eastern Mediterranean Sea.
The conclusion following the western investigation is that 28 out of 40 Peleio distances are close enough to be considered accurate, which is a 70% rate and hence shows the care the original cartographer has taken and the accuracy of the Peleio distances.

Diagram ChCPS/1/D14

Diagram ChCPS/1/D15

Diagram ChCPS/1/D16


I have treated the east slightly differently as here there is a major problem with the compass bearings for the main Peleio distances. The islands of Gozo Creti and Gozo Malta which nearly align geographically from Acre are not set at Ponente/levante as per the LCN, but some 10 and 13 degrees north of west. Many directions within LCN are observed correctly, but many are not, thus a dichotomy arises. The distance from Acre to Gozo Creti, LCN = 820 millara, but the Carta Pisane is 850 millara which is also the geographical distance. It is a minor change but so very important to the overall chart plot.
But read the Grazia Pauli text and the distance given is DCCCLX, or 860 millara.
However, from Gozo Creti to Gozo Malta, LCN has 800 millara, Carta Pisane has 765 millara and geographically it is 730 millara. Thus it is evident that the distance in LCN is overstated, has been corrected by the cartographer but not accurately enough. There are two further diagrams which discuss the eastern section; on one of which I have aligned a geographical plot based upon the distances Acre/Gozo/Gozo. It required that the geographical map be slewed to the southeast by between 10 and 13 degrees because of the imperfect alignment which is shown as a direct line on the Carta Pisane.
As can be observed on the diagram the correlation of the two charts is passable but when the second diagram is studied with the charts drawn correctly, not slewed, then the longitudinal correlation is very good. The correlation is illustrated on the putative latitudinal/longitudinal diagrams with the longitudinal lines north/south. But, I cannot state that had the directional information within LCN for the eastern Mediterranean Sea been geographical the Carta Pisane would be an accurate chart. But it is obvious there is an incredible underlying accuracy within the Peleio distances quoted in LCN.



Whence they came is a question that may never be answered.



To investigate the possibility it is necessary to draw the LCN plot for each and the overall distance plot from Genoa to North Africa, thus positioning these islands.
CORSICA: The diagram illustrating Corsica has two elements; first a coastal sailing route, “starea”, using LCN distances but set upon a geographical plot thus allowing errors to be noted and secondly the LCN text drawn to the same scale with the LCN directional element included. This exercise indicates that it is feasible at the drawn scale of the Carta Pisane to accept the LCN data and thus use the plot as a base for commencing Peleio measures.

SARDINIA: The diagram illustrating Sardinia likewise illustrates an acceptable profile when compared to the geographical profile and that the LCN errors tend to cancel each other out. Thus this could be as useful as the Corsica plot.



The third diagram in this section is illustrative of the overall distances when compared like for like. From Genoa to North Africa there is but 11 millara excess distance on the Carta Pisane but when visually compared the differences are marked between Sardinia and North Africa. Hence, the latitudinal problems of the Carta Pisane as already illustrated are now quantified.



Firstly, as the Leather/Vellum has been cut down there are two possibilities regarding the main features of the Carta Pisane, the wind roses. Have they been sized to suit the reduction or would they have been drawn differently. Certainly, if the Leather/Vellum had not been reduced in size there is no reason why the two circles could not be each 920 millara radius and thus the system of drawing the wind lines simplified. But accepting the Carta Pisane as it is, we must estimate the cartography accordingly. But the cut form must be discussed again.


A close study of the chart as portrayed upon the CD accompanying “Les Cartes Portolanes” appears to indicate that the first drawing task was the outline of the coast. I suggest an east/west line was drawn to ensure directional data was capable of being used and then a matrix of lines, Peleio distances were plotted. I believe a “master position” was chosen, possibly the Corsica/Sardinia plot to allow the Peleio distances to be plotted outwards thus gradually the matrix would take shape. Throughout the LCN there are hundreds of Peleio distances with directional information which if chosen carefully would link from
coastal feature to coastal feature thus triangulating and confirming positional data. The triangle is well known from the text by Ramon Lull and thus also the “Tavola de Navegare” such that it would be a natural usage for the cartographer.
In my “Lo Conpasso De Navegare” text I opined the following, which in the context of this paper is most apt.

This is a speculative idea which was formulated many years ago and is the reasoning behind my previous texts regarding the “Map within the Portolan Chart”. As I read and researched the 4 texts mentioned previously, which have finally all been available since 2011 (for the A Debanne text) this paper has been in my” to do” list.
The methodology I am about to explain in a few words is entirely feasible but requires foresight and aptitude to know that the Peleio distance/bearing data will yield this map.


From within “Lo Conpasso de Navegare” it was necessary to determine node points from which all else could be set out. Those node points must be geographically accurate enough to allow distances and bearings to be taken from them. They must also be located such that they are capable of being used to construct lines to any point of the compass, and for extensive distances in the Mediterranean Sea.


The islands of Corsica and Sardinia are described well enough when set against a geographical map to be capable of fulfilling those requirements. Thus the node points from the text for these islands were set down on a plain sheet of paper. Obviously there was no coastline, they just formed two shapes akin to rectangles set one atop the other, and were a series of dots or crosses.
Thus I had an accurate (relatively speaking) starting point to evaluate the whole western Mediterranean Sea. Using the Peleio distance /directions from the various node points on the two isles I am able by using compasses, protractor for bearings and a straight edge for distance measure to mark a series of dots or crosses representing the coastal features of Spain, France, Italy and North Africa. But importantly the various Peleio gave distance and direction measures to the same coastal features and thus by a simple triangulation I could pinpoint the actual locations of those coastal features using the compasses.
Therefore at the end of the exercise I had dozens and dozens of node points, coastal positions including the extra islands such as the Balearics for the western Mediterranean Sea.From here the competent cartographer could infill the coastline between these node points, concoct a shape, quite often just abstract curves and finish with a chart of the western Mediterranean Sea which will be geographical in its basis. The distances vis a vis the node points could be checked by the coastal data given in “Lo Conpasso de Navegare”, but it would also then show just how inaccurate the coastal data was by the Peleio positioning as now recorded. Originally the uncorrupted data may have proven the plot decisively.


Thus from a conclusion gained using just the coastal sailing data, that a chart could not be drawn, through an evaluation of the whole text and particularly the Peleio sections it is possible to construct a series of node points representing coastal features from which an actual coastline can then be constructed. We have moved from negative to positive.
Speculative this idea certainly is: the cartographers of c1300AD were certainly capable of carrying out this procedure and thus I am happy to set it down on paper for future discussion. But I consider the original map/chart to be the product of a monastic establishment in northern Italy, where the data for “Lo Conpasso de Navegare” was probably collated and the time could be spent gradually piecing together the Peleio information. This would be akin to the situation in Sicily c1150 when Al-Idrisi formulated his text and maps. It would have been a very slow laborious business suited to monastic life and not the world where the necessity to earn a living was paramount. Thus I finally comment that the monastic map was copied and circulated to form the basis of the Portolan Charts, and when the magnetic declination problem occurred the map was merely slewed on the Wind Rose which would originally have been as geographical as the map. Thus it is possible also that Giovanni Mauro di Carignano, a cleric in Genoa, knowing of the original “monastic” map decided that he could emulate the monastic community and produce a fine specimen of a Portolan chart.

Query; is this why I have found only a single chart, Riccardiana ms 3827 which could be considered the template for all others, because only a single copy of that original chart was available for outside use.

M J Ferrar 2015.



The close study of the chart and its ink lines appears to show that the two wind roses were drawn over the “Map within the Portolan”. Their size and position appears to indicate the cartographer was aware of the limited size of the Leather/Vellum as the “south” cartouche of the eastern wind rose has been twisted to suit the cut down size. Hence I believe it was cut down prior to the wind roses being drawn. But there is another possibility to be discussed later.


The next task was to draw the four rather imposing square scale areas using the 100 millara measure. They are aligned at various points to the main wind rose internal squares as the diagrams already shown indicate. Naturally however, because the wind rose internal squares are not 100 multiples there is only a single horizontal and vertical compliance normally indicated on the circumference of the circle. Why there are four is another matter!



The final task was to draw the diagonals to the 100 millara squares, which measure 71 millara each. They are merely a drawing exercise to infill the four areas, but it must be recognized that the 71 is the basic Root 2 unit and thus the diagonals could be drawn first and then the 100 millara squares would automatically follow. However, if the four areas are studied it is self evident that they are not all accurate, many lines wobble and in the southeast corner the lines are so badly drawn as to require bending to make junctions.
But what is also evinced by these squares is the state of the quills the cartographer has used. The original lines within the circles, red and black are well drawn with a good fine quill. But when the green ink is used the lines become progressively thicker as if the quill was wearing down exponentially until these last 45 degree lines at 71 millara centres are draw which are inordinately thick and very poorly drawn.
Study the CD presentation and the actual lines, their draughtsmanship, colours and thicknesses become so very real.


I have already discussed the fact that I consider the supposed reduction in the Leather/Vellum size to be prior to the drawing of the two wind roses and the four square distance features. But on a preceding diagram I indicated in green ink scribed or scratched lines which appear on the Leather/Vellum and the remains of a red line which does not accord with those drawn upon the Carta Pisane.


Do the four larger than necessary square distance features in fact mask a Palimpsest, an alteration in the basic presentation such that the original “Map within the Portolan” was drawn on a larger Leather/Vellum base, was revised by scratching out details and the four units used to hide the marks. The base material was then cut to remove unwanted drawing.
In other words, is the Carta Pisane originally a coloured/decorated map of the Mediterranean Sea basin which has been adapted to the Portolan Chart format with the wind roses?
It would take expert analysis in a laboratory and possibly X-rays to discover if there are any hidden features on the Leather/vellum. At the same time perhaps the Carta Pisane can be Radio Carbon dated and the necessity for reams of paper to be used to discuss its dating as is the wont of historians obviated. That would thus aid future cartographers and historians alike to focus upon fact and not nebulous ideas, and enable greater clarity for its origins.


If the Cartographer actually used the Peleio distances, constructed the chart and then used either his own knowledge of the coastlines or had available sketches of significant areas of those coasts to aid the overall composition then it is a “tour de force”.
Even if he was given a basic map to copy, drawn from the Peleio distances it is still a well executed Portolan chart, although there are many draughtsmanship issues to settle.
But if it is a reworking of an earlier map, this must be examined quickly.
Only a detailed forensic analysis of the Leather/Vellum base will indicate if the four overpowering square distance units were really necessary as a cover up, or the draughtsman perhaps just became carried away with drawing them on the chart.
The date of the Carta Pisane is a vexed question, but considering that Ramon Lull of Majorca wrote his “De Navigatione” and “Arbor Scientiae” c1295 where he postulated the calculations for sailing and correcting a ships position via an idea which is perhaps now the “Tavola De Marteloio” requires consideration. The first real exposition of the “Tavola” is given by Andreas Bianco in 1436, and followed by Michael of Rhodes in 1440, and thus we must question the date of 1290 that has been vigorously defended for the Carta Pisane.
As the first textual mention of the “Tavola de Marteloio” is dated 1390, it is now unfortunately open to all to speculate (more paper used) a date for the Carta Pisane. Ramon Lull’s texts are dated c1295 but there is the possible gap until 1390, some 100 years. However the knowledge would be known earlier than the 1390 text reference. But that presupposes the Carta Pisane was drawn in a place where the origins of the “Tavola de Marteloio” were to be found! Or, the cartographer knew the trigonometry ratios!
This research unequivocally illustrates that the 45 degree ratio of 71/71 is used for the construction of the Carta Pisane. Thus it also unequivocally proves that the wind rose was drawn geometrically and not via the 92 parts which were illustrated magnificently by Pietro Vesconte on his 1318 iconic wind rose diagram which incorporated a scale bar. The later Portolan Charts all use the 92 ratio, until size becomes an issue and geometry triumphs.
The Carta Pisane was not drawn from the “Starea” text of LCN as it is too nebulous for any accuracy which the chart exhibits. It is constructed from good data, possibly from a forerunner of the LCN, but from whence it actually came and from which century is another discussion which obviously must now take place in a separate text.
Thus I consider the research carried out thus far by others to be inconclusive and can only hope that common sense eventually prevails and the chart is analysed properly and these findings are incorporated. If not I suspect reams of paper will be wasted.

1 Ramon Josep Pujades I Bataller; The Pisana Chart; Really a primitive chart made in the 13th century. CFC (No216- Juin 2013)
2 T Campbell; A detailed reassessment of the Carte Pisane: a late and inferior copy. Or the lone survivor from the Portolan charts’ formative period. Conclusions.html.
3 Michael J Ferrar; ChCp/O; The Carte Pisane, Date Under Scrutiny? This is a paper sent to my site, It is only 4 pages and requires to be read to understand the logic of my texts.

The Carte Pisane, Date Under Scrutiny?
Occam’s razor and Commonsense Approach to the problem of dating the chart


Ramon J Pujades wrote 9 pages to set down his argument: Tony Campbell responded with 117 pages, text and tables. Before we waste a ‘forest’ for the paper and electricity of future papers, perhaps it is timely to look at alternate solutions, scientific and draughtsmanship.


In December 2012 at the Paris conference hosted by BnF, Ramon J Pujades i Bataller delivered a lecture concerning the dating of the Carta Pisane, a Portolan chart actually held by BnF, Paris. In his lecture he re-dated the Carta Pisane from a c1290 putative date to the early 15th century, c1420AD. The text which sets down the arguments for the re-dating was published in CFC, No 216, juin 2013, and consists of 9 pages of discussion, two pages of bibliography and five pages of chart abstracts.
On the 2nd March 2015, via the internet, Tony Campbell published 117 pages of text and tables which he hopes illustrate that the Carta Pisane Portolan Chart should in fact be held as the original putative date of c1290AD and thus the Cortona Chart re-established as c1300.

Necessary Preliminary Comments Of A Rather Bemused Independent Researcher.

Having studied many Portolan Charts and texts written concerning their format, I have found Cartographical Historians to be wanting in their analysis there-of, but was particularly taken by the honesty of R J Pujades when he freely admitted in writing, ’he had not researched the Carta Pisane, merely taken previous research as acceptable’. This led to confirmation of my earlier surmise noted in my papers that it is probably symptomatic of Cartographic Historians attitude, one of simple acceptance of data from perceived “collegiate” sources. I endeavour to test all evidence from the very beginnings of a charts existence and my paper referred to within this text proves that all others should also!
Now that I have read Tony Campbell’s statement; “However, since I lack the necessary mathematical skills, I have concentrated on the historical evidence, particularly that taken from the charts themselves”, I wonder just what has been missed with no mathematics, no draughtsmanship skills and forensic study of the whole basis of the charts.
Therefore at this point in reading the text I was completely nonplussed with the situation presented by both of the ‘protagonists’.
Cartography and Portolan Charts are all about mathematics and draughtsmanship. If the skill of historians is such that they cannot recognise drawing evidence of methodology on a chart, then perhaps it is time to re-assess the whole evidential base so far presented. I do not accept that the ‘History of Cartography’ is sacrosanct, even 1987 and 2007 are a long time ago! Neither do I accept the premise of “Deconstructing the Map” for historians benefit.
I will comment further upon this necessity later in this essay, but action is required now.

The Simplest Action Required To Be Taken

It worries me not that the Carta Pisane is dated to either c1290 or c1420AD, it is what it is.
What is so evidenced by the foregoing texts is that historians will write reams of pages with absolutely no chance of a final definitive resolution to that dating. This nonsensical situation must be resolved quickly and definitively. But, there is one method readily available to us.

Action Taken

To that end, in early March 2105,I wrote to the Director of the Departement des Cartes et Plans, at the BnF Richelieu-Louvois Bibliotheque to request a Radio-Carbon dating of a finely cut section of the Carta Pisane, taken from perhaps the Linguetta as the simplest and least obtrusive position. Thus I hope to obviate the necessity to continue with a vast quantity of words and text which will no doubt ensue. I cannot understand why this is not a regular tool.
If we accept that there is perhaps a timescale of c1290 to c1420 for the Carta Pisane, Radio-Carbon dating will clearly establish whether the actual date is closer to c1290 or c1420. Thus, there is the opportunity for at least three ranges of c40 years, a permissible system deviation.
Then perhaps a proper examination of the Carta Pisane can be undertaken with good evidence. Thus I suggest all wait for the Radio-Carbon dates before launching into the fray and thereby discussing a subject that is unknown to all, the actual date of the chart.
I will post another paper when and if the BnF actually respond to the request.

Necessary Discussion Emanating From Tony Campbell’s Text Which Concerns General Research Into Portolan Charts

NOTE WELL, I have already criticised the technical sections of R J Pujades texts and the work is posted online. Thus the following is restricted to the Campbell online text only.
The latest text by Tony Campbell focuses on 4 charts; Carta Pisane, Cortona, Lucca and Riccardiana. Three of these charts are illustrated within ‘Les Cartes Portolanes’ by R J Pujades; Carta Pisane, pp40/41; Cortona, pp66/67 and Riccardiana, pp104/105. The Lucca Chart is detailed within the text by Philipp Billion, ‘A Newly Discovered Fragment from Lucca Archives, Italy’. Imago Mundi 2011, vol 63, part 1, pp1-21
Campbell states (P3),”Had the chronological relegation of the Carta Pisane, Cortona and Lucca charts been endorsed the subject’s documented history would have started with the almost fully formed Vesconte chart of 1311. Nothing else except perhaps the Riccardiana Chart could have been placed earlier”.
Comment: This mystifies me; firstly I doubt any researcher has had the time to carry out research to endorse or not the new date: Lack of text is not lack of acceptance. Secondly, why did anything require to be placed earlier? I find the assumption there-in that because the Vesconte Chart is almost fully formed the documented history would somehow be wrong and because of that fact the Riccardiana chart should possibly be placed earlier. Why, because it is extant and included in Campbell’s nebulous collection of chart type and thus perhaps part of his linear system. Why is there no parallel system of chart development? Was there no prior development of the Vesconte chart we must allow for, or are we just accepting what we have is all there was? Surely not!
Campbell continues, ”The Carta Pisane’s less developed outlines than those visible on the earliest work of Pietro Vesconte, both there (Med Sea) and in the Black Sea, reveal the refinement that was about to take place between perhaps c1290 and 1311/1313”.


Comment: The argument put forward by Campbell appears to be that all chart development is linear: that if the Carta Pisane is dated to c1290 it is a precursor to the Vesconte 1311 chart; Why? What refinement can be established from one chart to the other as they are not linked?
Surely development of ideas is not linear but via a multitude of adjacent lines and thus the Carta Pisane and Cortona Charts (and perhaps even the Lucca Chart, {dated to perhaps 1311-1327 and thus parallel in time to the Vesconte Charts} and also the Riccardiana chart) could be seen as belonging possibly to the same branch of a tree which withers and dies and the Vesconte charts develop into the main trunk and branches. There is absolutely no necessity for the two sets of charts to be co-joined in this manner as their existence is probably not known by their individual draughtsmen. Do we have proof that each could have been known by the other? Do we even know where the Carta Pisane and the other charts were drawn for it to happen?
Campbell continues; “The main fault it finds (his text) with Pujades approach is the pre-supposition that Portolan charts were responsive, and speedily so, to geopolitical change or to altered mercantile relevance. The Pujades explanations are no doubt historically correct surmises, but can any definite instances of such chart making responsiveness be cited on Portolan Charts, to be set against the documented norms of delay and conservation?
In the few cases where we have a confirmed historical date for a new toponym, the average period before it reaches the charts is three generations
Comment; Thus we are asked to consider the fact that between the Carta Pisane of c1290 to the Vesconte chart of 1311, a mere 21 years, there is an exponential growth in cartographic presentation, the mathematics of a charts construction is set down for all to observe and in the Vesconte 1313 Atlas (also held by BnF), there is a seed change in the profile of the Atlantic Coast-line to a near geographical representation and the decoration is evolving.
Surely from c1290 to c1311/1313 to see such a change in that profile required the knowledge to be available even prior to c1290, to be worked on, set down in a preparatory manner thus allowing an ‘almost fully formed chart’ to be drawn later i.e.c1311.
If this can take place in 21 years, as Campbell suggests by his linear approach to the charts development, then the three generations or 60 years to add a toponym is fallacious and the few cases probably non-typical or it was not required to be placed urgently on the charts.

Evidence Contained Upon The Charts.
I have placed on my website the following text which has been refereed for a journal.

ChWr/1; The Wind Rose Construction on a Portolan Chart; Revisions to the origins of the Charts format as drawn.

It consists of 12 pages of text and contains 14 diagrams. It ends with the following; “Post-script; A Guide for the Perplexed” which explains the simple Medieval mathematical link of Marteloio and Portolan chart. The text uses the Portolan charts of Vesconte 1311 and 1321 (Atlas wind rose diagram); Dulceto 1330 chart; Carta Pisane and the Cortona Charts to illustrate the findings. A second very short text, ChWr/2 indicates the simplicity of it all.
This text I therefore consider relevant to the discussion that will no doubt ensue regarding the work of Pujades and Campbell whether the date is finally agreed or not. But although not included there-in, I have already analysed the Lucca Chart, Riccardiana Chart and the Carignano Chart in a similar manner and can in the near future upload a second text.


My latest text regarding the Wind Rose (ChWr/1) illustrates the complete lack of research by cartographical historians into the basic form of the Portolan chart, the very first lines to be drawn and the reason for that order. It also indicates that prior to a cartographical historian writing about a medieval chart or map they should consider requesting the advice of a cartographical draughtsperson to unravel the actual foundations upon which it is built. This text has unravelled the actual foundations of Charts and thus their scales and methodology. History can follow later and thus I suggest this evidence will prove a salutary lesson for all and “Deconstructing the Map” will be perhaps rewritten to understand technical cartography first.

Texts upon this website, Charts Page
ChAb/1; Andreas Biancho De Veneris Me Fecit M.CCCC.XXXvj
Atlante Nautico of Andreas Biancho Explained.
ChAb/2; The Ptolemaic Influence Upon Andreas Biancho, Atlante Nautico, 1436.
ChPo1; Portolan Charts; Construction and Copying
ChPo2; The map within The Portolan; Examination by redrawing.
ChPo3; Leather Vellum Parchment; Drawing and copying maps and charts
ChMa/1; Four Marteloio Investigated; Lull, Biancho, Michael Rodi and A N Other.
ChLcp/1; Les Cartes Portolanes; a critique of the technical sections there-in.
ChFb/1; Francesco Beccari, 1403 chart and Battista Beccari 1435 chart examined.
ChUg/1; Using a Portolan Chart at Sea, Did they? Practical or impractical for use by Mariner’s?
ChLCN/1; Lo Conpasso De Navegare, Can it be used to draw a Portolan Chart.
Carto-geographical Page
Cg1457; The Genoese World map investigated. Page (along with many other texts)
ChCo/1; A symmetrical Portolan chart; Cornaro atlas.
ChPo/4; Portolan; The Charts and the Myths; Three statements, three responses.
ChAc/1; Albino de Canepa, 1480 Chart.

M J Ferrar 2015.