13. Isabella I of Castile (1451-1504)
Although she is often linked to the Christopher Columbus legend as the ruler who sponsored the explorer’s travels to the New World, Isabella I of Castile was one of Spain’s most powerful queens. A devout Catholic, Isabella and her husband, King Ferdinand, tried to make Catholicism the main religion of Spain, despite the diverse faiths of the country, and ignited the Spanish Inquisition. Thousands of Spanish Jews were coerced into converting to Catholicism at the risk of being tortured and killed if they didn’t.
She was equally unfair to the country’s Muslim population. However, her belief in Columbus and her financial support of his voyages would eventually lead to the permanent European settlements of the Americas.