Beltrán joined Alfonso the Battler's final military expedition against the Muslim city of Fraga. He died in the Battle of Fraga on 17 July 1134, and the king died shortly after. The contemporary English chronicler Orderic Vitalis records that at Fraga the king ordered Beltrán to charge the enemy's camels. When Beltrán advised caution, the king accused him of cowardice and Beltrán promptly led a charge. The camels fled, but the pursuers were subsequently ambushed and massacred. The "Chronica Adefonsi imperatoris" records that Beltrán ("Beltran de Lannuces") was among the leaders at Fraga and that all the leaders were killed.