 Greek sources such as Diodorus Siculus' "Library of History" and Justin's "Epitoma Historiarum Philippicarum" recount that Darius fled out of fear at the Battle of Issus and again two years later at the Battle of Gaugamela despite commanding a larger force in a defensive position each time.At the Battle of Issus, Darius III even caught Alexander by surprise and failed to defeat Alexander's forces.Darius fled so far so fast that Alexander was able to capture Darius’ headquarters and take Darius’ family as prisoners in the process.