The Franciscan missionaries were not able to obtain from the natives an intelligible explanation of the events that had occurred which had caused the temples to be abandoned. But they were informed that an invasion had taken place about two hundred years before their arrival, and many of the caciques and ruling families had been driven out of the land. The invaders did not occupy the sacred buildings, and allowed them to fall into ruin, but they were visited occasionally by those who still had faith in the ancient gods and wished to offer sacrifices to them. It was ascertained that the greater part of Yucatan had become subject to the control of chiefs belonging to the Aztec race, and that several of them paid tribute to Montezuma. The question of the antiquity of the temples of Palenque, Uxmal and other structures of that character must therefore, in a great degree, be decided by the evidence upon which are based the traditions of the migrations of the Toltecs who preceded the Aztecs, and were the first of the hordes who conquered the aboriginal races of Central America. The historians who have investigated those traditions concur in considering that the arrival of the Toltecs within Mexican territory happened in the seventh century. After remaining some time in the northern part of the country, they migrated southwards to Cholula, Palenque and Yucatan.[104] If the historic evidence is accepted as being trustworthy, it follows that all the stone edifices in these regions must have been erected later than that date. The Aztecs arrived at the close of the twelfth century. Therefore it may be concluded that Palenque was built later than the eighth century, and was deserted before the fourteenth century. Uxmal is evidently more modern than Palenque, and it may be assumed that it was constructed after the tenth century, and abandoned not much earlier than a hundred years before the Spaniards landed upon the shores of the New World. The Aztec chiefs introduced into Yucatan one of their barbarous customs which was similar to what was practised by them elsewhere. It was found by the conquerors, that in Mexico they kept slaves and prisoners in cages, where these victims were fattened and prepared for sacrifice.[105] After having been killed and offered as propitiations to the gods their bodies were eaten. In 1511, it happened that a Spanish vessel was wrecked upon some shoals fifteen leagues south of the island of Jamaica. The crew after having been thirteen days in an open boat, landed upon the north-eastern shores of Yucatan near Cape Catoche, and were made captives by the cacique of the district. Valdivia, who was in command, together with four of his men, were at once sacrificed and eaten, others were put in cages, but several of these men escaped. When the fleet under the command of Cortes anchored off Cozumel, in 1519, one of the captives, named Aguilar, went on board the flagship.