King Ferdinand and Queen Isabella wanted to reconquer land controlled by muslims for christianity. They sent armies to battle a muslim group called the Moors for control over Granada.
In Spain, the Roman Catholic Faith was believed to be the one true faith. King Ferdinand and Queen Isabella used this to their advantage. Isabella believed that having everyone believe one faith will unite the country. Ferdinand saw this as an opportunity to control people. The Inquisition was used to judge anybody who did not believe in the roman catholic faith. Many people of other faiths fled.
The Spanish had a desire for exploration to discover new undiscovered lands. New routes of going west to reach East were already being explored by other countries. Queen Isabella and King Ferdinand sponsored Christopher Columbas because they believed Spain would benefit from the voyages.
In the 7ce, a Muslim group that goes by the name Moors, crossed over the Strait of Gibraltar from northern Africa and ruled over the Iberian Peninsula. The ruling monarchs of the kingdom of Aragon and kingdom of Castille and Leon felt like they needed to reclaim the land for christianity.
Here's the key to Granada
If the courts found an individual guilty, punishments would vary from confinement, dungeons, torture, or even death. If an individual was accused but not found guilty, their property was confiscated and forbidden from holding positions in any public office.
I will die for my religion!
In 1492, Christopher Columbas sailed west across the Atlantic Ocean and finding land in the Caribbean and claiming it for Spain. They chant, "GOD, GOLD, AND GLORY". God meaning god would reward them for spreading their Christian faith to the New World, gold meaning to acquire riches for themselves and their country(or country they represent), and glory meaning great power and larger empire.