Following Henry I's death in 1135, his daughter Matilda's claim to the English throne was usurped by her cousin Stephen, sparking a 19-year civil war known as 'the Anarchy' that devastated England. The conflict ended in 1153 when Stephen agreed to disinherit his son and recognize Matilda's line as his successor, largely because nobles refused to support a female ruler despite swearing oaths to uphold her claim.