The history of Guam involves phases including the early arrival of people known today as the ancient Chamorros, the development of "pre-contact" society, Spanish colonization, and the present American rule of the island. Archaeologists using carbon-dating have broken Pre-Contact Guam (i.e. Chamorro) history into three periods: "Pre-Latte" (BC 2000? to AD 1) "Transitional Pre-Latte" (AD 1 to AD 1000), and "Latte" (AD 1000 to AD 1521). Archaeological evidence also suggests that Chamorro society was on the verge of another transition phase by 1521, when Ferdinand Magellan's expedition arrived, as latte stones became bigger.