Colorado Colonial Records

History
Spanish conquistadors were the first Europeans to visit Colorado in the mid-sixteenth century. Juan de Ulibarri claimed the territory of Colorado in 1706, and in 1787 a failed attempt was made to establish the settlement of San Carlos. With the Louisiana Purchase in 1803, the United States acquired the eastern flank of the Rocky Mountains. Disputations with Spain and later Mexico over land were not settled until the mid-nineteenth century. During this time several trading posts were established and small settlements near the South Platte and Arkansas Rivers. In 1851, the first permanent European settlement, San Luis, was established by settlers from Taos, New Mexico.