Excerpts from Books and Wikipedia
"Empress Matilda . . . was one of the claimants to the English throne during the civil war known as the Anarchy. The daughter of King Henry I of England, she moved to Germany as a child when she married the future Holy Roman Emperor Henry V. . . . On Emperor Henry V's death, Matilda was recalled to Normandy by her father, who arranged for her to marry Geoffrey of Anjou to form an alliance to protect his southern borders. Henry I had no further legitimate children and nominated Matilda as his heir, making his court swear an oath of loyalty to her and her successors, but the decision was not popular in the Anglo-Norman court. . . . The throne was instead taken by Matilda's cousin Stephen of Blois, who enjoyed the backing of the English Church. . . . Matilda's forces captured Stephen at the Battle of Lincoln in 1141, but the Empress's attempt to be crowned at Westminster collapsed in the face of bitter opposition from the London crowds. . . . Matilda returned to Normandy, now in the hands of her husband, in 1148, leaving her eldest son to continue the campaign in England; he eventually succeeded to the throne as Henry II in 1154." [Wikipedia]