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In 2020 I commenced collating the necessary Portolan Charts for a paper to be entitled, “ChMAJ/1; Majorca and Messina influence on Portolan Charts. The Russus and Olives families; Historical.” The abstract was as follows; “Rather late in the context of Majorcan/Catalan influences, but having written text ChGME/1 linking those charts by author and teacher, basically finishing the text c1500, this text follows two cartographic dynasties from c1470 to c1640 with information on those who influenced them and whom they influenced.”

The first chart on the list was owned originally by Conte Giuliano Merenda of Forli, Italy. I could not locate it by a simple search and had to resort to a systematic search commencing with the data that Cartografia Mallorquina afforded me, as page 92 appended illustrates.



I firstly searched out the textual information available, particularly that by Uzielli and Amat (as now set down in the appendices) and obtained copies of texts and their appendices. It listed, “Elenco Degli Atlanti, Planisferi e Carte Nautiche” and on pages 45/46 a description;

“La Descritta Pergamena che attualmente trovasi in possesso del mio amico Giuliano Merenda in Forli, appartenevagia ad un suo ascendente, che nel secolo passato fu Cavaliere di Malta. (the described parchment that is currently in the possession of my friend Count Giuliano Merenda in Forli belonged to his ascendant who in the past century was a Knight of Malta). It is described as, ”Sec XV (fine) Carta nautical un foglio in pergamena rettagolare che misura m 0,74 x 0.97.” There then follows a descriptive text including the following;

“L’autore ei e indicato dalla sotto scrizione ‘Ego Petrus Rubeus di Messina composui hanc cartem ( qui manca un pezzo della pergamena) in civitates dicta gentilli, Anno domini, —– Amen” Thus no actual date existed on the chart.
I therefore commenced a search for Cont Giuliano Merenda and his family to trace the charts present where-about. The “Archivio Storico Anagrafico del Comune di Forli” produced a text attached here.


I had high hopes that this would produce the lead I required to the Merenda Family. That proved to be wishful thinking, even though the Merenda Pallazo still exists in Forli.
I searched for other papers regarding this chart and found in the Accademia Nazionale dei Lincei, Rome, a paper by Robert Alamagia dated 1957, “I lavori cartografia di Pietro e Jacopo Russo”. He stated, “if the attribution of the paper at the end of the 15th C is to be accepted, it would be earlier than that of Madrid; in any case note that not only did he work in Messina, but he was born there. Whether he belongs to or from the Majorcan map house, it does not appear” The full text is in the appendices.

I found that statement unacceptable as many cartographers merely gave an attribution as to where they happened to be living when their chart was drawn. But Almagia also included as footnote 5; “Op Cit, appendix Roma 1880 part II pp 45-47. Amat S Filippo ascribes the paper at the end of the 15th C >for extrinsic and intrinsic characters<, but it is not established if it was examined personally. Attempts made to examine the chart were unsuccessful”.

My immediate thought was that given the actual text by Uzielli and Amat, it had to have been seen or it could not have been totally described.
But the worrying thought was that if Robert Almagia could not find the chart to examine, had it vanished?
But having contacted the Forli Comune, Library and Museum, it suddenly provided a clue to the possible where-about of the Merenda Chart. Dott.ssa Lorenza Montanari, Funzionario Unit a Musei, Comune di Forli, responded to my enquiries with the enigmatic sentence; “At the Smithsonian Institute Washington, within the collection of the National Museum of History and Technology, a pilot book/portolano of Petrus Rubeus of 72.4 x 94 cms in dimensions, is kept”. It was pure luck the emails I sent came to her attention.


The Smithsonian Institute was completely shut down according to the anti-Covid regulations in force in the USA, but I found that some staff are working from home as was the norm in Europe. However, the first problem that I encountered was that the Forli information I was given was dated 1970 and a complete re-organisation at the Smithsonian Institute had taken place with the re-naming of certain divisions.

I therefore emailed the Archives enquiries and hoped somebody was on-line.
I was answered by Deborah Shapiro, an Archives Technician (reference) and with her expert aid I managed to surmount the problems I had encountered. Deborah Shapiro found a reference to a box in the Archives, Acc 03-071 and on another occasion D.S. managed to visit those archives and retrieve the box and its contents. I was also given a direct link to the collection record as follows;

Collection Creator; NM H&T division of Pre-Industrial Cultural History
Container Box 1 of 2
Citation S.I. Archives Accession 03-071 NMH&T, Division of Pre-Industrial Cultural History. Curatorial Records, and the EDAN –URL code.

I received a PDF copy of the contents which were an absolute game changer in the search, but there was no chart and more worrying there was no accession number or file number for it. What the data did point to was the fact that the Portolan Chart was part of an exhibition in the Cloisters of the Metropolitan Museum of Art NY, 1974/75 and the data included the text of the catalogue page of that exhibition for the chart. Also included was a text by Samuel Hessa, (see appendices) entitled, “A Portolan Chart in the collection of the Smithsonian Institute, Washington DC”, dated January 1970”. It is pages 5 -14 of the text which are a full description and attempt at dating it. But what pages 1-4 held I knew not. The paper was shown as being from the George Washington University, Washington DC and I immediately contacted the Gelman Library there to be told they knew nothing of the author or the paper.

My next foray was to the MET Cloisters who again were closed but some days later the curator responded to my enquiry, but yet again I drew a blank.
Deborah Shapiro had also suggested I contact Joan Boudreau, Curator of the Graphic Arts Collection. She had no knowledge of the chart and in fact did wonder if it referred to a Facsimile of a Portolan Atlas by “Joan Martines en Messina any 1582”.

Joan Boudreau then wrote again regarding the contents; “the link is for the collections in the SIA (access No 03-071) and Peter C Walsh correspondence, 1958/1970 with the subject of a Portolan Chart somehow included in those correspondences. My guess is that he is writing about the subject for the 1970’s Growth of the United States exhibition, so it is possible that there is no chart, just a discussion about one” That was not what I wanted to read.

Meanwhile Deborah Shapiro had been searching and found that the Exhibition in the Met Cloisters was entitled, “The Secular Spirit Life and Art at the end of the Middle Ages” and it had actually had a catalogue printed. A further search revealed it had been scanned and was actually available on-line and supplied me with the URL. I immediately downloaded it and there on page 150, item 170 was the text I had the original copy of plus a thumbnail in black and white of the chart itself. I immediately went back to the MET Cloisters and asked if their records showed who had actually supplied it and to whom it was returned. Again it was just Smithsonian Institute.
The page is here-in attached


Unknown to me, Joan Boudreau, Curator Graphic Arts had been searching and part of that was an email to other departments. This was noted by Paul F Johnston PhD, Curator, Maritime Collection, who replied as follows: “The piece is in Maritime Storage; I would call it an early chart, not really a portolan (IMO) and gave the following;
ACC230, 428/Cat.60.1654.”
That number 1654 had been written by an archivist on the Hessa Text!

I had started in May 2020 searching for the chart; in November 2021 I had a catalogue copy and in January 2022 I was sent a form to complete, pay 100 US Dollars and because of the lockdown it did not arrive until 02/04/ 2022 as a TIFF copy of the chart, Recto /verso.


The Petrus Rubeus chart in the Smithsonian Maritime Archives


The Cartografia Mallorquina contains the text written by persons who actually studied the chart, namely Uzielli and Amat in 1882. I have included that text and pages 45 and 46 from their appendix in my appendices. Plainly it is a very simplistic analysis describing the main features and the descriptive texts appended there-on. They state it is in a mediocre condition and the colours have faded but more importantly. “La leggende sono difficili a decifrarsi.”

The reference to U.A.;p280 item 474 is merely the basic bibliographical notes which are also attached here-in.

The next text I noted was by Robert Almagia, dated 1957 and I have already quoted his words concerning the date of the chart given as at the end of the 15th Century.

Therefore I can only turn to the text written by Samuel Hessa in 1970, but first note that the Portolan chart under discussion was purchased from Laurence Witten in 1959 by the Smithsonian Institute which probably accounts for the fact that in 1957, Robert Almagia could not view it.

I have attached the Hessa text as an appendix but take issue with much of it and those comments are best quantified by my own text concerning the actual charts format. However it is worth quoting two sections from pages 9 and 10 of the Hessa text.

Page 9; “The city of Constantinople is shown on the chart. Attached to it by thin lines are two small flags which have on them red crescents. These indicate that the city was, by the time of the construction of this chart, under Turkish control. Therefore the chart can be no older than 1453. As mentioned above, the Emirate of Granada is well represented on the chart. Granada was finally conquered in 1492. Therefore, the chart cannot be any younger than 1492.”

Page 10; “Thus, the chart has a relative date of post-1453, pre-1492. This is a period of 39 years. There does not appear to be any method of accurately pinning down the date within this period. It is the opinion of the writer that the chart was compiled during the early part of the period, probably around 1475. The principle reason for this opinion is that the Emirate of Granada is shown in an extremely definitive manner and covers a large chunk of territory. Surely if the map had been drawn in the 1480’s Granada would have been much smaller.”


Samuel Hessa raises two points; relative dates, post-1453 and pre-1482 with an opinion, “probably 1475”. He then states,”drawn in the 1480’s, Granada smaller”. That is much too simplistic and argument and must be challenged.

The armies of Ferdinand and Isabella very gradually re-conquered the area of southern Spain, but it was not until 1482 that the Muslim Emirate of Granada was under direct attack. Gradually Spain re-took town after town, but it was not until 1492 that Granada fell to the Spanish Army and the Muslim Emir, who had actually helped them achieve victory went into exile in North Africa.

That to my mind opens the date for this chart to between post-1453 to Hessa’s pre-1492 much closer and even later that 1492. Why? We must research the “Rubeus” dates first. We have to turn to the possible place of Birth and Training, that period will allow us to arrive at a date for Petrus Rubeus first chart. We know he drew a chart in 1508, it is dated, but the other two attributed are not, but are possibly 1509 and 1511. If the “Genlilli” chart was 1475 that gives an unlikely 33 years to the Messina chart of 1508.

My research for the text to follow this, ChMAJ/1, has the following; “trained in Majorca, 1480-1490, moves to Messina and Marries 1490-1495 and has a son Jacopo c1500”. To marry he had to be 21 years old. Thus he arrives in Messina, travels to Genlilli and produces the chart, which can only be after c1495”.

The fact that Petrus Rubeus still has the Emir seated in Granada is merely a hangover of information which occurs on many Portolan Charts. That though still produces a c12 year maximum to the second extant chart and depending upon travel times to be back in Messina for c1500 it could mean the other Genoa/Genlilli charts ( see BNF Paris sXV2) as he obviously returns there for the chart c1511.

There are many ífs’ and buts’, but logically the dates are valid, however, this chart is the work of a skilled artist, not a person producing his first chart and I suspect others precede this but now lost to us. That of course would place the date of this chart closer to 1495/1500, if it is the first, but much later if the skilled artist fact is taken into account.

(I am also researching the works of Al-Sharifi of Sfax and the M H Casais paper which deals with Granada and the method of its portrayal. On this chart Granada is shown as a green mound surmounted by a Bearded, Turbaned Face of the Emir and has a flag seemingly unattached. But as can be seen and M H Casais discusses instead of a Head it is normally a Pomegranate which is within the green mound.)


Ostensibly a standard Portolan Chart (see appendix text for fuller description), with a single wind rose graticule centred to the west of southern Italy and subdivided, 35/30/27 units. Scale bars are set north and south and represent the Miliaria of which 90 make a degree of latitude, which will be explained fully later.

The Mediterranean Sea Basin is drawn to be viewed from the south, but from the Danube River, Europe is drawn to be viewed from the north, including the British Isles. Unfortunately the Madonna and Child vignette is spoilt both by deteriorating ink and a large hole, but surprisingly for a chart drawn in “Genlilli”, the Madonna is completely surpassed by the Four “kings” heads drawn in N Africa. There is also a drawing of Prester John and another in Anatolia with a script beneath; “A questo es lu gran Turco de Constantinopoli in quaili es unu gran Signori”. Only one “king” is shown seated in a tent (Egitto), but to its left are four disjointed forms, then two further West looking very like legs with feet and not seen on any other Portolan Chart known to me.

Generally the vignettes of towns are small and named, but Venice and Genoa are considerably oversized in comparison. There are c53 flags and many towns without one. The town vignettes are actually copied several times for each type drawn, which is another feature on numerous charts which have towns illustrated.


The first part of my analysis was to evaluate the scale bars to ensure the measurements intended were known. The wind rose graticule was the first item to be assessed and it is a single square with no extra latitudinal or longitudinal lines, hence, it would be 184 x 184 units, the double proportion of 35/30/20/7 units. In this instance the 20 + 7 sections are combined to show only 35/30/27 graticules. Using the scale bars the square measures c3250SBU’s as each division of the scale bar is divided into 5 units. It should be noted that the overall graticule was obviously meant to be noted as a square given the space for extra lines on the chart.

But more importantly the overall graticule longitudinally marked the west coast of Iberia on the 9W longitude and the 36E longitude of the Levante Coast. That was quite remarkable as these two coasts are thus 45 degrees apart, 9W to 36E, and the square is c3250SBU’s. Thus there are 45 degrees longitudinally and each is therefore at c3250 length, 72.22 scale bar units. But given the scale bars are only 1200 SBU’s long the 45 degrees is actually 3240 SBU’s and thus the perfect 72 miliaria per degree, that is 80% of the 90 Miliaria latitudinal scale, the perfect cosine reduction used in the Middle Ages.

ChCGM/1/D05 & D06

But Petrus Rubeus had a second surprise for us in that the latitude of the wind rose graticule was 3240 SBU’s and if that is divided by 90/degree the resultant is 36 degrees. That is a perfect reverse mimic of the 36N cosine ratio of 5:4 as 36:45 is 4;5.

Petrus Rubeus on this chart has performed what for me is the first example of the wind rose graticule encapsulating the charts construct as the attached diagrams clearly show with the “normal” portolan chart skewing anti-clockwise as the error of the West Coast of Iberia drawn at 75 SBU’s when it should be 90 SBU’s causes.

Therefore the text by Samuel Hessa, page 8, is completely negated by this investigation, including the comment that the chart is based upon “compass” directions and distances.

I will also go as far as saying that as this is a 1970 text, and, by the time HOC was written in 1987 its findings were outmoded. However it is the first descriptive text written as the chart has been unseen from 1974 to 2022, some 48 years and obviously probably from 1882 to 1959 when it was purchased.

I have included Diagram ChCGM/1/D07 as a general basic setting out using the wind rose graticule to illustrate the fact that the wind rose lines are an important part of the design and would have been known for position and are thus probably originally first drawn.



The search I undertook to find this chart was thwarted by the global pandemic. I had already started another text which will follow, ChMAJ/1 and rather naively thought it was recorded and would be readily available.

Therefore until it is compared with the 1508 chart and the two BNF charts to understand Petrus Rubeus and his methodology, no actual conclusion is possible other than to re-iterate that it is a well drawn chart with an artist’s touch on the vignettes.

The text ChMAJ/1 will follow and hopefully answer all the loose ends.

Michael J Ferrar April 2022.


Accademia Nazionale Dei Lincei



Uzielli and Amat pages 45/47 and page 280
Smithsonian Institute original text for Metropolitan Museum of Art exhibition
Samuel Hessa text, pages 5-13 plus Bibliography etc








Michael J Ferrar April 2022.