Between 1067 and 1068, the War of the Three Sanchos involved him in a conflict with his first cousins, both also named Sancho: Sancho IV the king of Navarre and Sancho II the king of Castile, respectively. 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. The Navarrese Sancho begged the aid of the Aragonese Sancho to defend his kingdom. Sancho of Castile defeated the two cousins and retook both Bureba and Alta Rioja, as well as Álava.