The Clovis-First (or Late-Entry) model was proposed in the early 20th century after artifacts were unearthed in Clovis, New Mexico. These artifacts hinted at civilizations far older than previously assumed. Similar artifacts—including, most importantly, projectile points used to hunt game—were gradually unearthed across North and South America, even extending as far south as Tierra del Fuego. When Radiocarbon Dating was developed in the 1950s, the Clovis artifacts were dated to 11,500 years ago. Proponents of the Clovis-First Model believe that there was one definitive migration from Asia to pursue game animals. The Clovis-First Model remained the orthodox theory for many years; only recently has it begun to be edged out by the Early-Entry Model.