[1][2][b] Rodrigo's father, Munio Rodríguez, had in turn briefly rebelled against Fernando I of León and was forced by the king's soldiers to flee into the mountains.
[8] Rodrigo Muñoz first appears in 1073, when he joined his parents and the entire court in confirming a donation made by Pelayo, Bishop of León.
He appears on additional royal grants in 1080 and 1082,[9] in the latter charter as Rodericus Muniz Gallecie (Rodrigo Muñoz the Galician), a style that highlights his importance at court.
[9] Fought on 23 October 1086 between the armies of Alfonso VI and the Almoravid king Yusuf ibn Tashfin, the battle resulted in a decisive Leonese defeat and the loss of a significant portion of Alfonso's army, though Rodrigo is one of the few dead explicitly named.
Their own heavy casualties prevented the Almoravids from being able to capitalize on their victory, but it brought an end to Alfonso's expansion at the expense of the Muslim south.