Spain had a big head start in the exploration of North America, thanks to its investment in Columbus’s four voyages. Starting on islands in the Caribbean Sea, Spanish explorers and conquerors fanned out to various parts of the mainland.
One of the conquerors was Hernán Cortés, who used his army to conquer the Aztec empire in Mexico between 1519 and 1521. On the ruins of the Aztec capital, the Spanish built Mexico City. In 1535, Spain named its vast conquered territories New Spain, and Mexico City became the capital. But claiming land was only the beginning. The Spanish built settlements to protect their claims and to govern the people there. Without settlements, other European countries might move into the land Spain had claimed.