The comital house of Blois-Champagne that briefly held the English crown under Stephen, whose disputed reign plunged England into the civil war called the Anarchy.
The house sprang from the counts of Blois and Champagne, one of the greatest noble families of northern France. Stephen’s father, Count Stephen-Henry, was a leader of the First Crusade; his mother was Adela, a daughter of William the Conqueror, which gave Stephen a claim to the Anglo-Norman inheritance. Raised at the court of his uncle Henry I of England, Stephen was richly endowed and married the heiress of the county of Boulogne.
That combination — royal Norman blood, English and continental estates, and a powerful churchman brother — made Stephen one of the strongest men in the kingdom when Henry I died.
Henry I had made his barons swear to accept his daughter, the Empress Matilda, as his heir, but on his death in 1135 Stephen crossed swiftly to England and had himself crowned before Matilda could act. Many barons accepted him, but Matilda and her half-brother Robert of Gloucester pressed her claim, and by 1139 England was at war.
The struggle, remembered as the Anarchy, saw shifting fortunes: Stephen was captured at Lincoln in 1141 and briefly displaced, then restored; the chronicler’s phrase that "Christ and his saints slept" caught the lawlessness of a land fought over by rival garrisons for nearly twenty years.
The deadlock broke when Matilda’s son Henry of Anjou invaded in 1153 and Stephen’s heir Eustace died. By the Treaty of Wallingford, Stephen kept the crown for his lifetime but recognised Henry as his successor, disinheriting his surviving son William.
Stephen died in 1154, and Henry succeeded as Henry II, the first king of the House of Plantagenet. The house of Blois thus held the English throne for a single, troubled generation, remembered chiefly for the civil war its disputed succession unleashed.