The action began by the cavalry. As that of the Thebans were better mounted, and braver troops than the Lacedæmonian horse, the latter were not long before they were broke, and driven upon the infantry, which they put into some confusion. Epaminondas following his horse close, marched swiftly up to Cleombrotus, and fell upon his phalanx with all the weight of his heavy battalion. The latter, to make a diversion, detached a body of troops with orders to take Epaminondas in flank, and to surround him. Pelopidas, upon the sight of that movement, advanced with incredible speed and boldness at the head of the second battalion to prevent the enemy's design, and flanked Cleombrotus himself, who, by that sudden and unexpected attack, was put into disorder. The battle was very rude and obstinate; and whilst Cleombrotus could act, the victory continued in suspense, and declared for neither party. When he fell dead with his wounds, the Thebans, to complete the victory, and the Lacedæmonians, to avoid the shame of abandoning the body of their king, redoubled their efforts, and a great slaughter ensued on both sides. The Spartans fought with so much fury about the body, that at length they gained their point, and carried it off. Animated by so glorious an advantage, they prepared to return to the charge, which would perhaps have proved successful, had the allies seconded their ardour. But the left wing, seeing the Lacedæmonian phalanx had been broke, and believing all lost, especially when they heard that the king was dead, took to flight, and drew off the rest of the army along with them. Epaminondas followed them vigorously, and killed a great number in the pursuit. The Thebans remained masters of the field of battle, erected a trophy, and permitted the enemy to bury their dead. The Lacedæmonians had never received such a blow. The most bloody defeats till then had scarce ever cost them more than four or five hundred of their citizens. They had been seen, however, animated, or rather violently incensed against several hundred of their citizens, who had suffered themselves to be shut up in the little island of Sphacteria. Here they lost four thousand men, of whom one thousand were Lacedæmonians, and four hundred Spartans, out of seven hundred who were in the battle. The Thebans had only three hundred men killed; among whom were few of their citizens.