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.

You can help expand this article with text translated from the corresponding article in Spanish. (July 2012) Click [show] for important translation instructions. View a machine-translated version of the Spanish article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Consider adding a topic to this template: there are already 5,069 articles in the main category, and specifying|topic= will aid in categorization. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Spanish Wikipedia article at [[:es:Casa de Haro]]; see its history for attribution. You should also add the template {{Translated|es|Casa de Haro}} to the talk page. For more guidance, see Wikipedia:Translation.

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.

• Salazar y Castro, Luis, Historia genealógica de la Casa de Haro, Dalmiro de la Válgoma y Díaz-Varela, Madrid, 1959.
• Baury, Ghislain, "Diego López 'le bon' et Diego López 'le mauvais' : comment s'est construite la mémoire d'un magnat du règne d'Alphonse VIII de Castille", Berceo, n°144, 2003, p. 37-92.
• Baury, Ghislain, « Los ricoshombres y el rey en Castilla : El linaje Haro, 1076-1322 », Territorio, Sociedad y Poder : Revista de Estudios Medievales, 6, 2011, p. 53-72. .
• Baury, Ghislain, « La grande aristocratie et le système judiciaire dans le royaume de Castille (XIIe-XIIIe s.). Les sentences des ricoshombres du lignage Haro », Bruno Lemesle et Benoît Garnot (dir.), Autour de la sentence judiciaire du Moyen Âge à l'époque contemporaine, Dijon, EUD, 2012, ISBN 978-2-36441-028-2, p. 239-248.
• Baury, Ghislain, Les religieuses de Castille. Patronage aristocratique et ordre cistercien, XIIe-XIIIe siècles, Rennes, Presses Universitaires de Rennes, 2012, ISBN 978-2-7535-2051-6.

• Basque señoríos