He was the son of Ramiro I of Aragon and Ermesinda of Bigorre, and he succeeded his father in 1063. The Castilian Sancho was trying to retake Bureba and Alta Rioja, which his father had given away to the king of Navarre and failed to retake.
Sancho of Castile defeated the two cousins and retook both Bureba and Alta Rioja, as well as Álava. Sancho Ramírez followed his father"s practice, not using the royal title early in his reign even though his state had become fully independent. At first, the murdered king"s young son, García, who had fled to Castile, was recognized as titular king by Alfonso VI, while Sancho Ramírez recruited to his side noblemen of Navarre who resented their kingdom falling under Alfonso"s influence.
The crisis was resolved by partition.
Sancho Ramírez was elected King of Navarre, while he ceded previously contested western provinces of the kingdom to Alfonso. From this time, Sancho referred to himself as king not only of Navarre but also Aragon.
Sancho conquered Barbastro in 1064, Graus in 1083, and Monzón in 1089. A third marriage—to Philippa of Toulouse—is sometimes given, but contemporary evidence records him as still married to Felicia at the time of his death.
The Navarrese Sancho begged the aid of the Aragonese Sancho to defend his kingdom.
