One reason that madrid became the capital of Spain is because of its

One reason that Madrid became the capital of Spain is because of its location.

Explanation:

Madrid's history is known to have dated back to the 9th century when there was a castle built on the land by Muhammad I of Cordoba. This city was always characterized by its unique location, which made it the capital of Spain.

The city witnessed the invasion and birth of many reigns as Muslims were in control of the city until they were defeated in 1085 by the Christians who occupied the city after them.

After several years and due to its location, King Philip II moved the court there making it officially the capital of Spain, as during that reign, wherever the king goes, goes the government.

The Answer is:

Location