During the times of Christopher Columbus, the Queen and King of Spain sent Columbus to India, where he accidentaly "discovered" the Americas. There, he found rich resources such as minerals and gold. He stole the land from the natives living there and set up colonies and towns for Europeans to live in. Since Catholsism was an important part of Spanish culture, the Spanish monarchy decided to force the natives to Catholism in order to spread their religion. After seeing the success of Spain because of their exploration, other countries decided to venture out and explore accross the world, creating a huge expansion of territories for trade.
When the Aztecs saw an eagle perched on a cactus on the marshy land near the southwest border of Lake Texcoco, they took it as a sign to build their settlement there.
