1) In the early 1500s, Spain began exploring the Mariana Islands due to their strategic location for trade between Asia and Europe. This led to several encounters between the Spanish and the indigenous Chamorro people. 2) In 1521, Ferdinand Magellan landed on Guam due to low food and water supplies. A confrontation ensued when Chamorros boarded his ship and took items, leading the outnumbered Spanish to open fire and kill several Chamorros. 3) In 1565, Miguel Lopez de Legazpi arrived in Guam and formally claimed the island for Spain, establishing Spanish rule and bringing Augustinian priests to spread Catholicism among the native Chamorros.