This famous mosaic of a battle scene comes from the House of the faun in Pompeii. It is at the Museo Archeologico Nazionale Napoli. The battle is thought to be the Battle of Issus. Alexander the Great defeated the Great King of Persia, Darius III, at the Battle at Issus in November 333 B.C. Alexander's army was smaller than the Persian army -- no more than half the size, and possibly even smaller.