The Conquistadors were Spanish (than Castille) conquerors that were sent into the Americas by their king. The king sponsored numerous expeditions into the Americas, and the people that were sent were mostly military personnel. They were known as Conquistadors.
The reason why the conquistadors were sent into the Americas was that they can conquer as much land as possible for the Crown of Castille, and to gain access to the wealth there, primarily gold and silver. The Conquistadors did pretty much everything they could in order to get to gold, silver, and territory, destroying every advanced civilization in South and Central America, such as the Aztecs, Incas, Mayas (what was left of them) and many others. The Conquistadors were not only restricted in South and Central America, they also were active in the southern and western parts of North America.
