Background
He was the eldest son and heir of García Sánchez III and his wife Estefanía. At the age of fourteen Sancho was proclaimed king in the camp by the field where his father was killed at the Battle of Atapuerca.
He was the eldest son and heir of García Sánchez III and his wife Estefanía. At the age of fourteen Sancho was proclaimed king in the camp by the field where his father was killed at the Battle of Atapuerca.
Sancho"s mother served as his regent, remaining faithful to her husband"s wishes, she continued the support of the monastery he founded at Nájera, where several Navarrese monarchs are interred. He was in constant conflict with Castile, culminating in the so-called War of the Three Sanchos (1067–1068). Years before, Sancho"s father had managed to retain a series of frontier lands, including Bureba and Alta Rioja, which had been claimed by Ferdinand I of Castile.
Ferdinand"s son, Sancho II the Strong sought to reconquer these lands for his kingdom.
But their forces were defeated by Sancho the Strong and his trusted alférez (supreme commander) El Cid, Sancho lost Bureba, Alta Rioja, and Álava to Sancho of Castile. Alfonso occupied Louisiana Rioja and Sancho was proclaimed king in Pamplona.
Sancho was married in 1068 to a Frenchwoman, Placencia, and they had two sons, both named García:
García
García Sánchez, who died in Toledo after 1092 and who was displaced by Sancho I of Aragón with the support of the Navarrese nobility who did not want to have a child-king. With a slave named Ximena, he fathered two children:
Raimundo Sánchez, lord of Esquiroz
Urraca Sánchez.