After Empress Matilda released her rival King Stephen, he in turn released Robert of Gloucester, her strongest supporter, thus prolonging the Anglo-Norman civil war known as The Anarchy.

Empress Matilda, also known as Empress Maud, was one of the claimants to the English throne during the civil war known as the Anarchy. The daughter and heir of Henry I, king of England and ruler of Normandy, she went to Germany as a child when she was married to the future Holy Roman Emperor Henry V. She travelled with the emperor to Italy in 1116, was controversially crowned empress in St Peter's Basilica, and acted as the imperial regent in Italy. Matilda and Henry V had no children, and when he died in 1125, the imperial crown was claimed by his rival Lothair of Supplinburg.

Stephen, often referred to as Stephen of Blois, was King of England from 22 December 1135 to his death in 1154. He was Count of Boulogne jure uxoris from 1125 until 1147 and Duke of Normandy from 1135 until 1144. His reign was marked by the Anarchy, a civil war with his cousin and rival, the Empress Matilda, whose son, Henry II, succeeded Stephen as the first of the Angevin kings of England.

Robert FitzRoy, 1st Earl of Gloucester was an illegitimate son of King Henry I of England. He was the half-brother of the Empress Matilda, and her chief military supporter during the civil war known as the Anarchy, in which she vied with Stephen of Blois for the throne of England.

The Anarchy was a civil war in England and Normandy between 1138 and 1153, which resulted in a widespread breakdown in law and order. The conflict was a war of succession precipitated by the accidental death of William Adelin — the only legitimate son of Henry I — who drowned in the White Ship disaster of 1120. Henry sought to be succeeded by his daughter, Empress Matilda, but was only partially successful in convincing the nobility to support her. On Henry's death in 1135, his nephew Stephen of Blois seized the throne with the help of Stephen's brother Henry of Blois, who was the bishop of Winchester. King Stephen's early reign saw fierce fighting with disloyal English barons, rebellious Welsh leaders, and Scottish invaders. Following a major rebellion in the southwest of England, Matilda invaded in 1139 with the help of her half-brother Robert of Gloucester.