King Sancho I of León was a medieval monarch who ruled from 1065 to 1072. He was the son of Ferdinand I of León and Sancha of León. Sancho I is known for his efforts to consolidate power in the Kingdom of León and for his military campaigns against the Moors in the Iberian Peninsula. During his reign, Sancho I faced challenges from his brothers, particularly Alfonso VI, who would later become king. Sancho's rule ended when he was assassinated in 1072, leading to a power struggle that ultimately resulted in Alfonso VI uniting the crowns of León and Castile.