Portolan Chart of the British Isles f. 5
Cartographer: Conte Freducci
Medium: Ink and pigments on vellum
This is a portolan chart showing the British Isles. It is taken from a bound atlas bearing the inscription ":I H S: Conte Freducci Anconitano: la fatte: nel anno: Mo CCCCCoVIII" suggesting a date of 1508. 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. This portolan shows a pre 1550 representation of the British Isles, in that it does not includes an indentation on the coast of Wales, that would reveal knowledge of the Bay of Cardigan. Scotland is presented as an island linked by a small bridge of land to England. This is an invention of the chart maker Benincasa Grazioso which was copied and adopted by other cartographers of the period and beyond. Ireland is shown with the detail of the Purgatory of St Patrick included. This was a fabled internal lake populated by many tiny islands.