Sancho III Garcés (c. 992 – 18 October 1035),[1][2] called the Great (Spanish: el Mayor, Basque: Nagusia), succeeded as a minor to the Kingdom of Navarre in 1004, and through conquest and political maneuvering increased his power, until at the time of his death in 1035 he controlled the majority of Christian Iberia, bearing the title of rex Hispaniarum. Having gone further than any of his predecessors in uniting the divided kingdoms of Iberia, his life's work was undone when he divided his domains shortly before his death to provide for each of his sons. The Kingdom of Navarre existed for almost six centuries after his death, but was never as powerful again.

Sancho was born around 992 to García Sánchez II the Tremulous and Jimena Fernández, daughter of the count of Cea on the Galician frontier. He was raised in Leyra. His father last appears in 1000, while Sancho is first found as king in 1004, inheriting the kingdom of Pamplona (later known as Navarre). This gap has led to speculation as to whether there was an interregnum, while one document shows Sancho Ramírez of Viguera reigning in Pamplona in 1002, perhaps ruling as had Jimeno Garcés during the youth of García Sánchez I three generations earlier. On his succession, Sancho initially ruled under a council of regency led by the bishops, his mother Jimena, and grandmother Urraca Fernández

his father ( García Sánchez II, sometimes García II, III, IV or V (died 1000-1004),