Bermudo III of León

Bermudo III (1017 – 4 September 1037), king of León (1028 – 4 September 1037), son of Alfonso V of León by his first wife Elvira Mendes, was the last scion of Peter of Cantabria to rule in the Leonese kingdom. He was called Emperor in Galicia in 1025.

In 1029, Count García Sánchez of Castile was about to be married to Sancha of León, the elder sister of Bermudo, an arrangement apparently sanctioned by the king of Navarre, when the count was murdered in the city of León. Sancho III of Navarre then claimed the county of Castile in his wife's name and installed in it their son, Ferdinand, as the new count of Castile. The Navarrese king's policy turned to pure aggrandisement—sometimes ostensibly on behalf of his son and at other times simply on his own behalf. He seized the (linguistic) borderlands between the Cea and the Pisuerga rivers, right above León capital, long a bone of contention between León and Castile. After he had forced the marriage between Fernando and Sancha in 1032, those lands went to Castile as part of her also forced dowry. In 1034, he wrested the city of León itself from Bermudo, who retreated into Galicia. By the time Sancho died in 1035, the meseta north of the Duero was dominated by the Pyrenean pocket kingdom of Navarre.

However, for all of Sancho's diplomatic and military skill, one cannot help but think that such a situation was essentially the fortuitous result of having youthful opponents. Certainly the brute facts of geography and demography militated against its continuance. After his death, Bermudo III was immediately received back into León and soon began a campaign to recover from Castile and his brother-in-law the disputed territory between the Cea and Pisuerga. But Ferdinand defeated and personally killed Bermudo III at the Battle of Tamarón on September 4, 1037. Autopsy of his remains shows that he may have suffered death from infantry spears or pikes, after falling from his horse.

Since the latter died without an heir, the kingdom of León now recognized Sancha and her husband as its rulers, and Ferdinand was anointed king in the royal city on June 22, 1038. The dynasty of Navarre had triumphed perhaps, but the united realm of León and Castile with its rimlands of Asturias and Galicia, had become the political center of the north Iberian Christian society.

Marriage
By his wife Jimena, daughter of Sancho III of Navarre, Bermudo had one child, a son named Alfonso, who was born and died in 1030.