He was a son of Stephen, Count of Blois and his wife Adela, daughter of William 'the Conqueror' and was born in about 1096. Most of his reign was taken up with fighting his cousin, the Empress Matilda, for the throne.
In 1125 he married Matilda, daughter of Eustace III, Count of Boulogne and his wife Mary of Scotland.
Stephen of Blois, nephew of Henry I of England, was crowned on 22nd December 1135 (although some sources say it was on St Stephen's Day, 26th December), by William de Corbeil, Archbishop of Canterbury. He promised to all his Englishmen "all the liberties and good laws" which they had enjoyed under his predecessors. His queen was crowned the following year.
He died at Dover Castle on 25th October 1154 and was buried with his family at Faversham Abbey in Kent, which he had founded.
Oxford Dictionary of National Biography 2004