Theobald recommended him to King Henry II, who made him Chancellor (1155). Becket became a successful and trusted friend and adviser. Henry sent his son, also called Henry, as a page to Becket's household.
When Theobald died, Henry made Becket Archbishop of Canterbury (1162).
As Archbishop, Becket became much more religious. He started doing godly acts, such as wearing a hair shirt.
The manner of his death, murder at the hands of Henry's knights, shot him to fame. 15 biographies were written within 20 years of his death. The Pope made him a saint. His shrine became the most popular in England and was the destination of Chaucer'spilgrims in the Canterbury Tales.
The Pope claimed authority over all kings and bishops. The bishops were powerful landowners who acted as the king's advisers.
If a cleric was accused of a crime, he was not tried in the king's court. Instead, he was tried in a Church court where the punishments were not so strict.
The Popes were able to convince many knights to earn forgiveness for their sins by going on Crusade against Muslim control of Jerusalem and the Holy Lands. An act that protected the Church's power and led to centuries of such Crusades.
He reformed the law. He set up the jury system and ordered that only royal judges, called Justices, could try criminal cases. Henry II is sometimes called 'the Father of the Common Law'.
He expanded the lands and wealth within his empire by conquering Ireland in 1172
In 1164 he introduced the Constitutions of Clarendon, a code of 16 rules designed to increase the king's influence over the bishops and the Church courts. Henry demanded that, if the Church courts found a cleric guilty, they had to hand him over to the king's court to be punished properly. He felt the appointment of Becket as Archbishop (effectively in charge of religion in England) assured him of his aim. There could only be one lord on Earth in England. Was it to be the church or the monarch?