The first two gave the Spanish title to Columbus's discoveries and any other non-Christian western lands discovered as long as the native populations were converted to Christianity. The third limited this "western" area to all the lands beginning one hundred leagues west of the Cape Verde and Azores islands. This bull actually gave the Spanish rights to the far East by western circumnavigation. The fourth bull, the Dudum Siguidem, which was issued later on August 26, 1493, nullified any previous papal orders that had favored the Portuguese.
With Spanish control of the Caribbean and Gulf of Mexico assured, Spain proceeded to colonize the islands in the area (Hispaniola, Puerto Rico, Jamaica, and Cuba), converting the islanders as they went and often massacring whole populations purposely or accidentally killing them by transmitting European diseases. The main goals in the expansion were to Christianize the Indians (as dictated by the pope), to gain trading power, and of course, to "acquire" the great mineral wealth of the Americas. This mineral wealth included vast amounts of gold and silver ore. The reports of opulent Mexican empires brought back by explorers on Francisco Hernandez de Cordoba's and Juan de Grijalba's coastal journeys caused the Spanish government to look inland.
Cortes.
Hernan (also Hernando or Fernando) Cortes was born in Medellin, Estramadura, in Spain in 1485 to a family of minor nobility. Cortes was sent to study law at the University of Salamanca in 1499. After intermittent studying for two years, he left school to fight in a military expedition in Italy but became ill and was forced to stay behind. In 1504 he left to seek his fortune in the West Indies, arriving in Hispaniola and fighting in various battles against the Arawak. Cortes later participated in the conquest of Cuba with Diego Velazquez, the future governor, and gained the latter's respect.
After the reports from the coastal expeditions of Cordoba and Grijalba reached Velazquez in 1517 and 1518, the governor became determined to make full contact with the mainland empire and gain riches for Spain, converts for the Church, and fame for himself.