Answer:
The marriage of Ferdinand and Isabella helped to unify Spain as they led the reconquest of Spain from centuries of Christian rule.
Explanation:
The couple was known as the Catholic Monarchs. With their marriage the kingdoms of Castile and Aragon were united. This union gave the Catholic Monarchs an unprecedented political, economic and military power, which allowed them to start conquering the other kingdoms of the Iberian Peninsula, the vast majority controlled by Muslims, who had conquered the territory in the 8th century. The Spanish Reconquista ended in the year 1492, with the conquest of Granada.
