Ferdinand II was the king of Aragon and Isabella I was the queen of Castile. Aragon and Castile were the 2 major kingdoms in different parts of Spain. However they were unified by marriage, but they ruled the kingdoms independently
Ferdinand II and Isabella I was also known as Catholic Monarchs.
Ferdinand and Isabella wanted bring royal authority back in Spain. So, they made their own police force called "The Holy Brotherhood", it enforced laws and kept the nobles in check, and also made their own court system.
They also move from one city to another instead of keeping one city as their capitol city.
For many years the Jews were expulsed from many different regions, because the Catholic church doesn't believe in what the Jews or Muslims believe in, but there were a lot of Jews in Spain till 1492, an order all Jews and Muslims to leave Spain, as Catholicism was the only accepted religion. But then Ferdinand allowed them back only if they switched to Christians.
A famous event of the time of Ferdinand and Isabella was the Columbus's journey. They funded his journey in return for a payment when he founded his destination. This brought riches to the Spain.
Isabella wanted Spain to continue to be peaceful even after her reign, so she organizes marriages for her 5 daughter, with England, Portugal, Wales, the H.R.E(Holy Roman Empire) and the Hapsburg Dynasty.
Then in 1492 in Spain, was the most important time for Spain