The early inhabitants of the Philippines arrived in multiple waves of migration, beginning hundreds of thousands of years ago with Homo erectus. The first settlers were the Negritos, followed by groups from Indonesia and later Malays who arrived by boat. Arab traders introduced Islam to the Sulu Islands in the 1300s. Prominent Muslim missionaries helped establish sultanates and convert much of the population in Mindanao and Sulu to the Islamic faith. Today, there remain ethnolinguistic Muslim groups scattered across the southern Philippines who have preserved Islamic traditions introduced centuries ago.