Saint Thomas Becket was an English nobleman who served as Lord Chancellor from 1155 to 1162, and then notably as Archbishop of Canterbury from 1162 until his murder in 1170. He is venerated as a saint and martyr by the Catholic Church and the Anglican Communion. He was engaged in conflict with Henry II, King of England, over the rights and privileges of the Church and was murdered by followers of the king in Canterbury Cathedral.

Becket was possibly born in 1119, according to later tradition, at Cheapside, London, on 21 December, the feast day of St Thomas the Apostle. He was the son of Gilbert and Matilda Beket. Gilbert was perhaps related to Theobald of Bec, whose family was also from Thierville.

Theobald entrusted him with several important missions to Rome and also sent him to Bologna and Auxerre to study canon law. In 1154, Theobald named Becket Archdeacon of Canterbury, and other ecclesiastical offices included a number of benefices, prebends at Lincoln Cathedral and St Paul's Cathedral, and the office of Provost of Beverley. His efficiency in those posts led Theobald to recommend him to King Henry II for the vacant post of Lord Chancellor, to which Becket was appointed in January 1155.

Becket was ordained a priest on 2 June 1162 at Canterbury, and on 3 June 1162 was consecrated as archbishop by Henry of Blois, the Bishop of Winchester and the other suffragan bishops of Canterbury. Henry may have hoped that Becket would continue to put royal government first, rather than the church, but the famed transformation of Becket into an ascetic occurred at this time.

A rift grew between Henry and Becket as the new archbishop resigned his chancellorship and sought to recover and extend the rights of the archbishopric. This led to a series of conflicts with the King, including one over the jurisdiction of secular courts over English clergymen, which accelerated antipathy between Becket and the king. Attempts by Henry to influence other bishops against Becket began in Westminster in October 1163, where the King sought approval of the traditional rights of royal government in regard to the church. This led to the Constitutions of Clarendon, where Becket was officially asked to agree to the King's rights or face political repercussions.

King Henry II presided over assemblies of most of the higher English clergy at Clarendon Palace on 30 January 1164. In 16 constitutions he sought less clerical independence and weaker connections with Rome. He used his skills to induce their consent and apparently succeeded with all but Becket. Finally, even Becket expressed willingness to agree to the substance of the Constitutions of Clarendon, but he still refused formally to sign the documents. Henry summoned Becket to appear before a great council at Northampton Castle on 8 October 1164, to answer allegations of contempt of royal authority and malfeasance in the Chancellor's office. Convicted on the charges, Becket stormed out of the trial and fled to the Continent.

Henry pursued the fugitive archbishop with a series of edicts, targeting Becket and all Becket's friends and supporters, but King Louis VII of France offered Becket protection. He spent nearly two years in the Cistercian abbey of Pontigny, until Henry's threats against the order obliged him to return to Sens.

Becket fought back by threatening excommunication and an interdict against the king and bishops and the kingdom, but Pope Alexander III, though sympathising with him in theory, favoured a more diplomatic approach. Papal legates were sent in 1167 with authority to act as arbitrators.

In 1170, Pope Alexander sent delegates to impose a solution to the dispute. At that point, Henry offered a compromise that would allow Thomas to return to England from exile.

In June 1170, Roger de Pont L'Évêque, Archbishop of York, was at York with Gilbert Foliot, Bishop of London, and Josceline de Bohon, Bishop of Salisbury, to crown the heir apparent, Henry the Young King. This breached Canterbury's privilege of coronation and in November 1170 Becket excommunicated all three.

On hearing reports of Becket's actions, Henry is said to have uttered words interpreted by his men as wishing Becket killed. Interpreting Henry’s wish as a royal command, four knights, Reginald FitzUrse, Hugh de Morville, William de Tracy and Richard le Breton, set out to confront the Archbishop of Canterbury. On 29 December 1170, they arrived at Canterbury and killed Thomas inside the cathedral.

After his death, the monks prepared Becket's body for burial. Soon after, the faithful throughout Europe began venerating Becket as a martyr, and on 21 February 1173, he was canonised by Pope Alexander III in St Peter's Church, Segni. In 1173, Becket's sister Mary was appointed Abbess of Barking as reparation for the murder of her brother. On 12 July 1174, amidst the Revolt of 1173–74, Henry humbled himself in public penance at Becket's tomb and at the church of St. Dunstan's, which became a most popular pilgrimage site.

Other Saints of the Day
1. Saint Aileran
2. Saint Albert of Gambron
3. Saint Dominic
4. Saint Ebrulf
5. Saint Trophimus of Arles

- catholic.org