Saint Thomas Beckett was born around 1118 in Normandy to a well-to-do family. He was educated in Paris and was later made Archdeacon of Canterbury when he went to England. He was introduced to King Henry II in 1154 and he was well liked by the King. Henry made Beckett one of his advisers, and when the Archbishop of Canterbury died in 1161, the King wanted Thomas to take his position, thinking that he could benefit from having a loyal friend in the position. However, this was not the case.
Beckett upheld his position strictly for the Church. He did not let the King get away with anything, and was eventually forced to flee to France. He excommunicated the Bishops of London and Salisbury for their cooperation with the King, causing further turmoil.
The King ordered several knights to kill the Archbishop, and when he was confronted, he accepted his fate. Saint Thomas of Beckett was martyred on December 29, 1170 at the altar of Canterbury Cathedral, where his tomb now lays. (1)

In response to Thomas' decision not to side with the king on everything, the king issued the Constitutions of Clarendon, which declared that clerics charged with serious crimes were to be tried in secular courts and other royal rights over the church. When Thomas was summoned to a trial, he fled to France. Upon his return to Canterbury, he was murdered by four of the king's knights in the cathedral. His tomb was visited by the king as an act of penance and thusly became a site of pilgrimage. (5)

Thomas actually had a military career. He even led the English army into battle. When he was made the new Archbishop, many clergymen were upset because Thomas wasn't a priest and was known to be extravagant, as well as a harsh commander.
However, he soon became the opposite. He was charitable to the poor, helping 13 poor people every day. He started wearing a hair-shirt and getting whipped. He even slept on a stone floor to repent his sins. (2)


This is an image of Saint Thomas of Beckett. [3]


This is a picture of Beckett right before he was killed. [4]


Sources
(1)http://www.eyewitnesstohistory.com/becket.htm
(2)http://www.spartacus.schoolnet.co.uk/NORbeckett.htm
[3]http://www.spartacus.schoolnet.co.uk/NORbeckett.htm
[4]http://www.lamp.ac.uk/history/Images/becket
(5) http://www.answers.com/topic/thomas-becket