Tirso Julián Francisco José Ramón María de Olazábal y Lardizábal was born into a distinguished and aristocratic Basque family, with many of its members recorded in history of the region. The Olazábal family is reputed to be one of the first settlers of the province of Guipúzcoa, taking part in the exploits of Cantabria. They also contributed to the restoration of Spain with Pelagius of Asturias and accompanied Ferdinand the Saint in the Siege of Seville and in several incursions into Andalusia. Considered to be a chief lineage or a lineage of "Elder Relatives" ("Parientes Mayores") of Guipúzcoa, its founders owned the fief of Alzo, where they possessed the patronat of San Salvador Church. The first official document of the province of Guipúzcoa, dated 1025, attributes to the Olazábal family the property of 300 "caseríos" (villages) in the place of Alzo.