House of Haro

The House of Haro was one of the most powerful families of Castile during the Middle Ages, which strongly supported the expansionist policies of Alfonso VI of Castile. As a reward, Íñigo López was named the first Lord of Biscay.

In the early 16th century, the Haro family married paternally into the House of Sotomayor establishing a branch that would go on to hold dominion over the Marquesado del Carpio established in 1559 by King Philip II of Spain.