Polities founded in the Philippines from the 10th–16th centuries include Maynila, Tondo, Namayan, Pangasinan, Cebu, Butuan, Maguindanao, Lanao, Sulu, and Ma-i. The early polities were typically made up of three-tier social structure: a nobility class, a class of "freemen", and a class of dependent debtor-bondsmen. Among the nobility were leaders called "Datus", responsible for ruling autonomous groups called "barangay" or "dulohan". When these barangays banded together, either to form a larger settlement or a geographically looser alliance group, the more esteemed among them would be recognized as a "paramount datu", rajah, or sultan which headed the community state. Warfare developed and escalated during the 14th to 16th centuries and throughout these periods population density is thought to have been low. The Luções from Luzon then had economic and military influence in South, Southeast and East Asia. In 1521, Portuguese explorer Ferdinand Magellan arrived in the area, claimed the islands for Spain, and was then killed by Lapulapu's fighters at the Battle of Mactan.