Villehardouin (vēlärdwăNˈ) [key], French noble family that ruled the Peloponnesus from 1210 to 1278. Geoffroi I de Villehardouin, d. 1218, nephew of the historian and marshal of Champagne and Romania, set out on the conquest of Morea (as the Peloponnesus was then called) in 1205, with his friend Guillaume de Champlitte. With some 100 knights the two men rapidly subdued the Greeks, who were beset by internal quarrels, and, in 1205, Champlitte proclaimed himself prince of all Achaia. On the return of Champlitte to France, Villehardouin succeeded him (1210) as prince. Achaia, organized on the feudal model of the Latin Kingdom of Jerusalem, comprised virtually the whole Peloponnesus save several ports held by the Venetians, and it was a fief held under the Latin Empire. Its capital was Mistra, near Sparta. The principality prospered under the strong rule of Geoffroi I and of his son Geoffroi II de Villehardouin, d. 1246, who like his father was an excellent administrator. Geoffroi II's brother and successor, Guillaume de Villehardouin, d. 1278, was a warlike prince. Captured (1259) at the battle of Pelagonia by Emperor Michael VIII of Nicaea, who in 1261 was to recover Constantinople and to restore the Byzantine Empire, he refused to accept freedom in exchange for the cession of Achaia. In 1262 the so-called Ladies' Parliament, held by the wives and widows of the captive or slain nobles of Morea, met some of Michael's demands and ceded the Greeks a foothold in SE Morea, including Mistra but not Sparta, which became the new Latin capital. Released, Guillaume gained the alliance of King Charles I of Naples and Sicily, to whom he gave the hand of his elder daughter, Isabelle, and who received (1267) the nominal suzerainty over Achaia from the exiled Latin emperor, Baldwin II. Guillaume's death in 1278 ended the male line of Villehardouin.