Alfonso I (more rarely Alonso), called the Catholic (el Católico), was the King of Asturias from 739 to his death in 757. He was son of Duke Peter of Cantabria, and held many lands in that region. He may have been the hereditary chief of the Basques (Vascos), but this is uncertain. He is said to have married Ormesinda, daughter of Pelayo, who founded the kingdom after the Battle of Covadonga in which he reversed the Moorish conquest of the region. He succeeded Pelayo's son, his brother-in-law, Favila on the throne after the latter's premature death.

Whether Pelayo or Favila were ever considered kings in their own lifetime is debatable, but Alfonso certainly was. He began a lifelong war against the Moors. In 740, he conquered Galicia and in 754, León. He went as far as La Rioja. However, the populations of these frontier regions fled to his northern dominions, leaving a depopulated buffer between the Christian and Moslem states.

This created the so-called "Desert of the Duero," an empty region between the River Duero and the Asturian Mountains. Alfonso intended it this way; he wished to leave such a zone where any invading army would find it too difficult to survive. Besides the martial, the demographic and cultural effect of this policy on later Asturian and Spanish history is large. It was over a hundred years before the region was repopulated (an event known as the Repoblación).

The Arab writers who speak of the Spanish kings of the northwest as the Beni-Altons, appear to recognize them as a royal stock derived from Alfonso I.

Asturian monarchs | 757 deaths

Alfonso I | Alfons I d'Astúries | Alfons I. (Asturien) | Alfonso I de Asturias | Alphonse Ier des Asturies | Alfonso I delle Asturie | Alfons I van Asturië | Afonso I das Astúrias | Альфонс I (король Астурии)