Of all the medieval kingdoms in the Iberian Peninsula probably the Kingdom of Castile was the one more related with England. Eleanor of England, daughter of Henry II and Eleanor of Aquitaine, was queen of Castile by her marriage to Alfonso VIII and was a key player in the kingdom, including the paramount victory over the Muslims in the battle of Las Navas de Tolosa (1212). Her daughter Blanca of Castile was queen of France and, before being crowned, played an important role when her husband, Dauphin Louis, invaded England in 1215. And another Eleanor, descendant of the first one, travelled back to England, married to the future Hammer of the Scots, Edward I, who built a path of crosses to mark her last trip to be buried at Westminster Abbey. Not to talk about The Black Prince and his involvement in a Castilian Civil War, taking back with him not only the notorious Black Prince’s Ruby, but also two Castilian brides for his brothers John of Gaunt (Constanza) and Edmund of Langley (Isabel). The daughter of John of Gaunt and Costanza, Katherine of Lancaster, was the first Princess of Asturias and later Queen of Castile. Edmund of Langley’s wife, Isabel, was the first Duchess of York and great grandmother of two English kings, Edward IV and Richard III.
But how and when was the Kingdom of Castile born? To answer that question we need to go back to the 8th century, when the Iberian Peninsula was invaded by the Muslims in 711. They easily overthrew the Visigoths who ruled the country after the collapse of the Roman Empire. But as early as 722 the invaders were defeated by a local army in the Northwest in the battle of Covadonga. The Spanish nationalist propaganda turned later this victory as a heroic fight of a desperate handful of men against more than one hundred thousand enemies, but probably it was not more than a skirmish about a tax payment. Nevertheless, the winners gained their freedom and that was the beginning of the Kingdom of Asturias, who started to spread all over the Northwest of what is now Spain and Portugal. It was divided into counties. The one located in the East frontier was the one that suffered the bitter part of the attacks from the Muslims and it was filled with fortresses to defend itself. Accordingly, the Muslims called that territory Al-Qila (the castles); the name Castile was born. A man called Rodrigo was the first known Count of Castile in the year 860.
In the early 10th century the capital of the Kingdom was transferred from Oviedo to Leon, about 60 miles to the South and not so isolated by mountains as the former capital. The Kingdom of Asturias became the Kingdom of Leon.
But, as we have said, in the 10th century Castile was not a kingdom but a county of the Kingdom of Leon. There was a key figure in the way to Castile’s Independence. His name was Fernán González and he was Count of Castile from 932 to 970. Spanish nationalism of the 19th century proclaimed him as the man who achieved the county’s independence from Leon, but although he managed to secure a great autonomy of Castile, who became a capital force in political decisions of the Kingdom of Leon, and he made the county hereditary to his descendants, Castile didn’t declare his independence during González’s government. Neither did his son García Fernández, his grandson Sancho García nor his great grandson García Sánchez.
We will have to wait until the year 1037. At this moment the King of Leon was Vermudo III, who had no sons. Her sister Sancha was married to the Count of Castile by the name of Fernando Sánchez. There were several territorial conflicts between Leon and Castile and, as usually happens, the conflicts turned into a war. The armies of Leon and Castile faced each other in a place called Tamaron on August 30th 1137. As a result of the battle, King Vermudo III was slain. Count Fernando presented his claim to the throne through his wife Sancha, sister of the defeated king. It was not an easy path; understandably, the magnates of the Kingdom were reluctant to handle the crown to Vermudo’s killer. But with not too many alternatives and after a year of fight and negotiations, the count was crowned as Fernando I of Leon in 1038. He was later known as Fernando I el Magno (the Great).
Fernando ruled as King of Leon, and Castile continued to be part of the Kingdom, but he didn’t proclaim himself King of Castile, so the county didn’t became a kingdom during Fernando’s reign. It would be after his death in 1065 that he divided the kingdom among his three sons: Alfonso inherited Leon, García was appointed King of Galicia and Sancho became the first independent King of Castile. So, it was in 1065 that the Kingdom of Castile was born. There were several problems between Castile and Leon before the two kingdoms were definitely united in 1230 under the rule of Fernando III the Saint. Fernando was the grandson of Eleanor of England, Queen of Castile, and the father of Eleanor of Castile, Queen of England.