Complex sentence: The cartographer cross-referenced Ancient Latin place names for areas around the Mediterranean and Western Europe with contemporary equivalents as well as provided place names to areas unknown in Ptolemy's era (such as areas around the Caspian Sea in Central Asia).
Split into simpler sentences: The cartographer cross-referenced Ancient Latin place names for areas around the Mediterranean and Western Europe with contemporary equivalents. The author also provided place names to areas unknown in Ptolemy's era (such as areas around the Caspian Sea in Central Asia).