What was the dominant religion of Spanish?

The dominant religion of Spain is Roman Catholicism. Catholicism was introduced to the Iberian Peninsula by the Romans and became the official religion of the Visigoths, who ruled Spain from the 5th to the 8th centuries. After the Muslim conquest of Spain in the 8th century, Catholicism was suppressed in most of the country, but it survived in the northern kingdoms of Asturias, León, and Castile. In the 10th century, these kingdoms began to reconquer Spain from the Muslims, and Catholicism was gradually re-established as the dominant religion. By the end of the 15th century, all of Spain was under Christian rule, and Catholicism was firmly established as the country's official religion.

Today, Catholicism remains the dominant religion of Spain, with over 75% of the population identifying as Catholic. However, there is also a significant minority of other religions, including Protestantism, Islam, Judaism, and Buddhism.