Battle of Tamarón

The Battle of Tamarón (in Event locality::Burgos took place on Event data::4 September 1037 between Ferdinand, Count of Castile and  Vermudo III, King of León. Ferdinand had married Vermudo's sister  Sancha while Vermudo was married to Ferdinand's sister Jimena of Navarre (c1020-c1067). Ferdinand defeated and killed his double brother-in-law near Tamarón after a brief war. As a result, Ferdinand succeeded Vermudo on the throne.

Ferdinand's father, Sancho the Great, who was jure uxoris Count of Castile, had entrusted his son with the county as early as 1029. In 1034 he had conquered the imperial city of León and forced Vermudo to take refuge in remote Galicia. After Sancho's death in 1035 Vermudo returned to León and launched a war for control of the Tierra de Campos, the territory between the Cea and Pisuerga rivers, long disputed with Castile (which was nominally a Leonese vassal). The dispute dated back to the tenth century. Under Sancho the Great the region had been united to Castile, and Ferdinand considered it as his wife's dowry. Recently, Gonzalo Martínez Díez has disputed this thesis, first enunciated by the Historia silense in the 1110s. He finds no evidence for any discord between Castile and León in the years 1035–7, and the lands between the Cea and Pisuerga, controlled by his father, do not seem to have been controlled by Ferdinand.

What is certain is that the war in which he lost his life was initiated by Vermudo. Ferdinand, who also had a claim to be the heirless Vermudo's successor through his wife, was forced to call on his brother García Sánchez III of Navarre, because the Leonese forces greatly outnumbered his own. In the ensuing battle, Vermudo fell from his horse, Pelayueol, and was surrounded and killed while trying to approach Ferdinand. Seven of his knights died with him. Autopsies performed in the twentieth century showed that he had received forty lance wounds, many in the lower abdomen, typical for dismounted knights. After the death of Vermudo his army probably evaporated; there is no further discussion of the battle in the sources: the king's body is said to have been carried off the field. After his victory Ferdinand took possession of León after a brief siege and was accepted as Vermudo's successor, though he was not crowned in León until 22 June 1038. Vermudo was buried in the Panteón de los Reyes in the Basilica of San Isidoro in his capital.