Mindanao is named after the Maguindanaons who constituted the largest Sultanate historically, and evidence from maps made during the 17th and 18th centuries suggests that the name was used to refer to the island by natives at the time. Evidence of human occupation dates back tens of thousands of years. In prehistoric times the Negrito people arrived. Sometime around 1500 BC Austronesian peoples spread throughout the Philippines and far beyond.
Courtesy: Wikipedia