Carta Pisana

[3] It is the oldest surviving nautical chart (that is, not simply a map but a document showing accurate navigational directions).

[3][4] It is a portolan chart,[4] showing a detailed survey of the coasts, and many ports, but bears no indication on the topography or toponymy of the inland.

[2] As to the date of the map, it is partly indicated by the mention of the town of Manfredonia, which was founded by king Manfred of Sicily in 1256.

However, there is absolutely no evidence supporting the existence of an earlier portolan chart, and the fact that the map's most glaring error concerns Italy would undermine the theory of an Ancient Roman influence.

[4] The exact value of these "portolan miles" is difficult to calculate in present-day units, given discrepancies between geographical areas on this map and others; but it is conventionally accepted to be around 1.25 kilometers.