Coming to power in 1369, the House of Trastámara was a lineage of rulers of the Castilian and Aragonese thrones. The line of Trastámaran royalty in Castile ruled throughout a time period of military struggle with Aragon. Their family was sustained with large amounts of inbreeding, which led to a series of disputed struggles over rightful claims to the Castilian throne. This lineage ultimately ruled in Castile from the rise to power of Henry II in 1369 through the unification of the crowns under Ferdinand and Isabella.