Diego López V de Haro, nicknamed el Intruso, was a Castilian noble of the House of Haro and held the title of the Lord of Biscay which he took from the pretender to the title, John of Castile.

Bilbao is a city in northern Spain, the largest city in the province of Biscay and in the Basque Country as a whole. It is also the largest city proper in northern Spain. Bilbao is the tenth largest city in Spain, with a population of more than 347,000 as of 2023. The Bilbao metropolitan area has 1,037,847 inhabitants, making it the most populous metropolitan area in northern Spain; with a population of 875,552, the comarca of Greater Bilbao is the fifth-largest urban area in Spain. Bilbao is also the main urban area in what is defined as the Greater Basque region.