Portolan Chart of Western Europe Showing British Isles
Medium: Ink and tempera on parchment
This is a portolan chart showing the British Isles. It is orientated with south at the top. Invented by Italian mariners, Portolan charts take their name from the Italian ‘Portolano’, meaning a written description of 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. Scotland is joined to England by a narrow bridge of land and the depiction of Scotland shows a squat foreshortened land mass. The Bay of Cardigan is not included, an omission typical of depictions of the Welsh coastline in the first half of the 16th century. The depiction of Ireland includes the mythical Purgatory of St Patrick, an internal lake containing over three hundred tiny islands. Flags are posted on Ireland and Scotland with the red cross of England decorating the centre of the compass rose.