A brilliant diplomat, he changed dramatically when created Archbishop of Canterbury (1162).
To Henry's displeasure Becket resigned his chancellorship and became a strict defender of the special priviliges of the clergy and the canon law of the papacy. He thus came into conflict with the king's policy which was designed to keep the clergy in subordination to the state. He fled the country after having his goods confiscated.

In 1170 he was reconciled with Henry II, and returned to Canterbury. The friendship did not last, new quarrels errupted, and on 29 Dec. 1170 Becket was murdered in Canterbury cathedral by four of the king's knights. He was canonized in 1173, and Henry did public penance at his tomb in 1174.
The Death of Thomas Becket