Spanish Conquistadores conquered the Aztec, Inca, and Maya Empires together with the help of other native american tribes. They took large territories in North, South America, Asia, Africa, and Oceania. Spain made these territories into Viceroyalties until the XIX century. Spain, especially the kingdom of Castile, became much more powerful. Also, through royal marriages, the Spanish monarchs created alliances with other European powers. This allowed the Spanish Empire to gain control of many territories in Europe. With all these territories and colonies across the world, the Spanish Empire became the greatest and richest empire in the world.