Sancho III of Navarre
After the death of Sancho III of Navarre, his empire was divided. García, the eldest son, received the Kingdom of Navarre, while younger son Ferdinand already controlled what was then the County of Castile, owing fealty to his brother-in-law, Bermudo III of León. In 1037, with Garcia's help, Ferdinand defeated and killed the childless Bermudo at the battle of Tamarón, and claimed the crown of León in right of his wife, Bermudo's sister, being crowned in 1038. He rewarded García by ceding to him Castilian territories from Oca to the gates of Burgos, from Briviesca to the valley of Urbel, from Castrobarto to Bricia, and from the Nervión River to Santander.