Wolof history probably dates to about the 12th or 13th century. Wolof forefathers migrated west to the coast from Mali following the defeat of the Empire of the Ghana in the 11th century. Oral family histories indicate that at least some of the first settlers in the area were of Fulbe origin. Much Wolof history has been preserved in oral praise songs which are recited by griots ("professional praise singers"). Portuguese traveler accounts from the 15th century indicate an organized Wolof presence in what is still their homelands. Europeans established a fort on Gorée Island off the coast of modern day Dakar, which served as one of the primary points of departure for slaving vessels bound for the Americas. Since European contact Wolof history has undergone numerous conquests and revolts as competing rulers challenged one another for kingship.