Jaun Zuria ("The White Lord") is the mythical first Lord of Biscay. According to the legend, he was born from a Scottish princess that had been visited by god Sugaar in the village of Mundaka. The 15th century warlord Lope García de Salázar adapted a history from the Libro dos Linhagems by Pedro Alfonso, making Jaun Zuria a noble elected by the Biscayne people to lead them against a Leonese army in the mythical battle of Arrigorriaga.
Another version makes Juan Zuria an Irish prince named Lemor MacMorna. While hunting with his brother Armin in the forest he killed his father with a stray arrow. Lemor was set adrift in a small boat with two other warriors and washed up on shore in Mundaka. King Lekobide of Euskadi offered him sanctuary in the valley of Padura and Lemor fell in love with his daughter Luz. Lemor slew the invading Leonese King Ordoño, was given the respectful name Zuria (The White Lord) and became the first lord of Biscay.
It has been suggested that Jaun Zuria is the same person as Olafr inn hvíti (Olaf the White), a Viking-Irish king who lived in the second half of the 9th century.
The historical Lordship of Biscay was created by the Castilians after they conquered the territory of Navarre in 1200 and the story serves to legitimise their dynasty.
Reference: Bilbao, Jon. “Sobre la leyenda de Jaun Zuria, primer señor de Vizcaya” in Amigos del País, hoy, Real Sociedad Vascongada de Amigos del País (Comisión de Vizcaya), Bilbao, 1982, pp. 235–263.