Achaea was founded in 1205 by William of Champlitte and Geoffrey I of Villehardouin, who undertook to conquer the Peloponnese on behalf of Boniface of Montferrat, King of Thessalonica. With a force of no more than 100 knights and 500 foot soldiers, they took Achaea and Elis, and after defeating the local Greeks in the Battle of the Olive Grove of Koundouros, became masters of the Morea. The victory was decisive, and after the battle all resistance from the locals was limited to a few forts, that continued to hold out. The fort of Araklovon in Elis, was defended by Doxapatres Boutsaras and withstood the attacks until 1213, when the garrison finally surrendered. The fort of Monemvasia, and the castles of Argos, Nauplia and Corinth under Leo Sgouros held out until his suicide in 1208. By 1212, these too had been conquered, and organized as the lordship of Argos and Nauplia, and only Monemvasia continued to hold out until 1248. William of Champlitte ruled Achaea until he departed for France to assume an inheritance, but died on the way there in 1209. He was succeeded by Geoffrey I of Villehardouin, who ruled until his own death in 1219.