Henry II became a good friend of Becket but the friendship did not last. In 1161 at the time of Theobald's death Becket realised the job of Archbishop of Canterbury was much more serious than that of Chancellor and that he would have to protect the Church from plans that Henry II had for it. The reason was that Henry wanted to bring order to the judicial system as at the time the Church had its own courts. The Church did not want to be part of a system which in the past had put them on the same level as serfs.
Archbishop of Canterbury
Henry forced Becket to become Archbishop thinking Becket would help move his plans forward but in October 1163 Henry put forward his plans before the Council of Westminster and Becket opposed them. Henry Attempted to move his plans forward at the Council of Clarendon but again Becket refused to comply. Henry then decided to crush Becket and at a meeting at Northampton in October 1164 planned to accuse Becket of being a traitor and to imprison him.
Becket fled the country and went into exile under the protection of Pope Alexander III who himself was in exile in Sans due to conflicts caused by the Papal election. Becket's land was confiscated by Henry II. In June of 1170 Henry II used Becket's enemy the Archbishop of York to assist in the coronation of his son Henry, the Young King.
After the coronation of the Young King Henry II left England and met Becket to discuss the conflict between them. After a series of meetings the two men came to an agreement and Henry agreed to allow Becket to return to England and reclaim his lands. On December 1st 1170 Becket returned to England and on Christmas day gave a sermon at Canterbury Cathedral. During the sermon he excommunicated several men. At the time Henry II was in Normandy and at the news that Becket was excommunicating bishops who he thought had opposed him the King became extremely angry. Four knights overhearing Henry's pleas to rid himself of Becket took the King at his word and travelled to England to deal with Becket. On December 29th the knights found Becket in Canterbury Cathedral and were unable to get the Archbishop to reverse the excommunications he had served. The knights drew their swords and tried to remove Becket from the church but in the struggle that ensued the Archbishop was hit on the head with a sword and was killed. Thomas Becket was buried inside Canterbury Cathedral and his shrine became an important place for visiting pilgrims. Henry II accepted the part he played the Becket's death and took the punishment of whipping by the monks of Canterbury.