PTOLEMY, C. - Taprobana Ins. Tabula XII Asiae. [Sri Lanka.]

Ptolemy's mythical island of Taprobana originally became associated with Sri Lanka although it was sometimes confused with Sumatra. Taprobana, as it was called on most early maps, was an important post for trade between the east and the west, and was drawn too large on many maps because of its importance.
But Marco Polo states: It has a circumference of some 2400 miles. And I assure you that it used to be bigger than this. For it was once as much as 3500 miles, as appears in the mariners' charts of this sea. But the north wind blows so strongly in these parts that is has submerged a great part of this island under the sea.
To the left a text box explaining that Taprobana is surrounded by 1378 islands.
The line across the lower part of the island represents the equator, and the numbers below the line indicate the degrees east of Ptolemy’s prime meridian in the Canary Islands.

Taprobana was the historical name of an island in the Indian Ocean. It was first reported to Europeans by the Greek geographer Megasthenes around 290 BC, and was taken up by Ptolemy.