In 1162, King Henry II of England appointed his Chancellor and close friend Thomas Becket as Archbishop of Canterbury, expecting Becket to subordinate the English church to royal authority. Instead Becket underwent a dramatic transformation, becoming a fierce defender of ecclesiastical independence against the crown. The conflict escalated over years of exile, negotiation, and confrontation, culminating in Becket's murder in Canterbury Cathedral in December 1170 by four knights acting on Henry's expressed frustration — one of the most shocking political crimes of the medieval West.

Becket's martyrdom became one of the most productive subjects in medieval European literature. Within a generation, hagiographic verse-lives, Latin hymns, vernacular saint's plays, and devotional poetry proliferated across England and France. Chaucer's Canterbury Tales (c. 1387–1400) opens with pilgrims journeying to Becket's shrine, embedding the saint in the foundational monument of English literary culture. T. S. Eliot's Murder in the Cathedral (1935) demonstrates the enduring poetic resonance of Becket's story.