Portolan Chart of Western Europe Showing the British Isles(001ADD000025442U00005000)
Cartographer: Battista, Agnese
Medium: Ink and pigments on vellum
This is a portolan chart from a bound atlas dating from 1564. It is the work of Battista Agnese, a chart maker from Genoa, who prepared many portolan Atlases in the 16th century. Invented by mariners, portolan charts take their name from the Italian ‘Portolano’, meaning a written description of Catalan and Italian ports along a coastline. The first portolan Charts date from the late 13th century and represent an important change in the use of maps and charts. Until this point, most maps had held a religious significance and purpose, such as the medieval mappa mundi which was based on theological beliefs. The portolan chart contrasts with this tradition as they are based on direct observation and first hand experience and have a practical purpose. Reflecting their use by sailors they note only coastal locations, omitting most of the internal detail of the land. Place names are written at right angels to the coast, the more important ports in red ink. The lines which cover this and all other portolan charts are lines of constant bearing known as rhumb lines. These radiate from compass roses and allow the sailor to plot a course from harbour to harbour using dividers and straight edge. Here England and Scotland are joined by a bridge of land and colours are used differentiate the countries. The year that this chart was produced was the year that the Bay of Cardigan was first accurately depicted in printed form by Gerard Mercator. Perhaps reflecting this development Agnese shows an indentation on the Welsh coast line, contrasting with his earlier works which present a smooth outline for Wales. The Scottish coastline is also improved upon, a development also to be credited to Gerard Mercator whose map of 1564 presented such an improved version of the Scottish coast that it was to remain unchanged for almost 100 years.