After William's death there began a struggle over who would wield the most power—the king or the nobles—and how much authority the king should have over the church. William II and Henry I, sons of William the Conqueror, strengthened the crown at the expense of the nobility. The barons regained much of their power under King Stephen but lost it again under Henry II (ruled 1154-89), in part because of their frequent fights among themselves.

Henry was the first of the Plantagenet kings. He extended the authority of the royal courts and fostered the growth of English common law. Henry established the jury of presentment—ancestor of the grand jury system—which presented charges against suspected criminals. (Formerly charges had to be brought by private individuals.)

Henry's effort to gain greater authority over the church led to a bitter conflict with Thomas Becket, archbishop of Canterbury. Becket was murdered in 1170 by knights from Henry's court. Pope Alexander III, enraged at Becket's murder, required Henry to do penance, even though there was no proof that he ordered the murder.