Sancho I was Ordoño III’s stepbrother because, although Ramiro II was their father, they had different mothers. Muslim historians explain that Sancho was pretentious and proud, but extremely disliked above all due to his size: he was so big that he couldn’t even ride a horse, and therefore couldn’t direct his troops during war. This is why he is known as “El Craso”, meaning nothing short of “The Fat”.
In 958 Sancho I’s cousin, Ordoño Adefónsiz, son of king Alfonso IV (926-931) “El Monje”, rebelled against him. The rebellion was successful, and Ordoño IV rose to the throne. Sancho had to flee to the Pamplona kingdom. There, his maternal grandmother, Mrs. Toda, came up with a plan for him to recover the kingdom. First, she went with him to Córdoba, where he was well received by Abderramán III. The caliph provided the service of his own personal doctor, the jew Hasday ibn Saprut, who forced Sancho to follow a harsh herb based diet. After a while he reached an average weight and was able to go back to riding
horses. Abderramán granted him a sizable army, and that way, in 960, he went back into León and reclaimed the throne. Ordoño IV took refuge in al-Ándalus, where he died a few years later.
Similarly to the previous kings, Sancho also had to suppress rebellions within the kingdom and cope with muslim attacks that focused mainly on Castilian territories. He passed away in 966, seemingly after eating a poisonous apple. His son Ramiro succeeded him, who was still a five year old child.