"It appears to be not only the oldest known portolan atlas on whose charts any part of the New World is laid down, but the oldest known atlas in which the coast regions of a very large part of the entire world are represented with a fair approach to accuracy." - Edward Luther Stevenson
Early photographic facsimile composite made by the early map expert Edward Luther Stevenson around 1910 or 1911.
The Egerton Portolan atlas is an absolutely fascinating early map of the Americas, which is not well enough studied or known among contemporary map scholars. The rendering of the Caribbean invites comparison to the woodblock Peter Martyr map of the same year.
In Atlas of Portolan Charts: Facsimile of Manuscript in British Museum (the preparation for which was certainly tied to the production of the present facsimile) Stevenson wrote:
Although neither signed nor dated, the several charts exhibit certain features which suggest the authorship of Vesconte de Maiollo, and in the astronomical tables, on fol. 11b, an argument may be found for assigning it to the year 1508. The historian Henry Harrisse thought it might be 1507 but Johannes Denucé showed that the New World nomenclature was based to a considerable extent on the 1508-09 voyage of Juan Dias de Solis and Vicente Pinzon, which gives 1510 as the most probable date for such a map to have been made in Italy. There is no trace in the detailed charts of Balboa's discovery of the South Sea in 1513, which sets a limit to the time when the maps were made. Cortesao followed Denucé in dating it 1510 and there can be no doubt that this date is a dose approximation to the year it was drawn. Whoever the author may have been, he must be credited as one possessing the skill of an expert draughtsman, the good judgment of an intelligent map-maker, and the knowledge of a geographer who endeavored to keep himself informed concerning the most recent discoveries.
Edward Luther Stevenson was among the most important scholars of early cartography active at the end of the 19th century and the first half of the 20th. He was responsible for numerous cartobibliographic books, including the first translation of Ptolemy to English, as well as a series of impressive facsimile maps produced while he was at the Hispanic Society of New York. Dr. Stevenson viewed facsimiles as integral to the study of early cartography, and he committed himself to building an unparalleled collection of photographs of early maps and globes. Much of his collection was donated to Yale University after his death (click on the title link above for about that), but the present item comes from a large collection of photos, manuscripts, and related material that were part of Stevenson's library, but were not donated to Yale. It is truly an impressive collection and many of the items, though reproductions, have serious antiquarian merit. As Alexander O. Vietor said about Stevenson collection that went to Yale "this is the stuff of which great libraries are made."