 However, a clash outside the walls of Mantinea with Athenian cavalry foiled this strategy as well.Realising that the time allotted for the campaign was drawing to a close, and reasoning that if he departed without defeating the enemies of Tegea, Theban influence in the Peloponnesus would be destroyed, he decided to stake everything on a pitched battle.What followed on the plain in front of Mantinea was the largest hoplite battle in Greek history.