Angelino Dulcert, an Italian Majorcan, apparently got his hands on some ancient maps taken by the Crusaders from Constantinople, maps which the Muslims about 700 years previously had taken to Constantinople from Alexandria, maps which Dulcert compiled for his map in 1339 showing very accurately the Mediterranean all the way to the Black Sea in the east, and in the west, the eastern Atlantic coast accurate up to the Hebrides (off the western coast of Scotland), but very inaccurate depictions by medieval mapping imprecision added-on of the Baltic Sea and of Mesopotamia, thus proving that the accurate portions of the map were from ancient source maps. (See Page titled Great Pyramid for Navigation to see how the ancient accurate source maps used by Dulcert were drawn.)
