Early battles with the phalanx usually resulted in similar formations pushing against each other until one broke. The potential of the phalanx to do more was shown at the Battle of Marathon (490 BC). Facing the huge army of Darius I, the Athenians thinned out their phalanx and lengthened their front to avoid being outflanked. However, even a reduced-depth phalanx proved unstoppable to the lightly armed Persian infantry. After routing the Persian wings, the hoplites on the Athenian wings wheeled inwards, destroying the elite troop at the Persian centre. This was a crushing victory for Athens. Throughout the Greco-Persian Wars the hoplite phalanx continued to defeat the Persian infantry (e.g. the battles of Thermopylae and Plataea).