Lucio Russo has speculated about a probable arrival of Phoenicians in the Americas in his philologic analyses of Ptolemy's Geography.[15] In his book Ptolemy gives the coordinates of the Fortunate Isles but at the same time he shrinks the size of the world by one third compared to the size measured by Eratosthenes.[16] Russo observes that by attributing those coordinates to the Antilles, the world gets back to the right size, the geographical description given by Ptolemy fits much better and certain puzzling deformations in Ptolemy's world map disappear. Russo argues that the Antilles coordinates must have been known to Ptolemy's source, Hipparchus. Hipparchus lived in Rhodes and may have gotten this information from Phoenicians sailors, since they had full control of the western Mediterranean in those times.