Canterbury Cathedral traces its institutional origin to 597, when Augustine arrived from Rome to lead a mission to the Anglo-Saxon kingdom of Kent. King Æthelberht provided a base in Canterbury, and Augustine became the first archbishop in an enduring succession. Archaeology and texts indicate several early churches on the site, repeatedly altered before the Norman Conquest. After 1066, Archbishop Lanfranc replaced the Anglo-Saxon cathedral with a large Romanesque church, and Anselm's generation extended the eastern end and crypt to serve a Benedictine monastic community and the growing authority of the see.

A central event occurred on 29 December 1170, when four knights killed Archbishop Thomas Becket inside the cathedral after his conflict with Henry II. Becket's rapid canonization turned Canterbury into one of medieval Europe's major pilgrimage destinations. Fire destroyed much of the Romanesque choir in 1174. William of Sens and William the Englishman rebuilt the eastern arm in the new Gothic style, creating the Trinity Chapel and Corona around Becket's shrine. Stained-glass miracle windows narrated cures attributed to the saint and presented pilgrimage as both devotional practice and institutional memory.

Later medieval work transformed the western portion. The nave and transepts were rebuilt in Perpendicular Gothic form from the late fourteenth century, and the central Bell Harry Tower rose around the turn of the sixteenth. Monks managed worship, hospitality, estates, books, and the shrine economy until Henry VIII dissolved the priory in 1540. Becket's shrine was destroyed by royal order, its treasures removed, and his cult officially condemned. A dean and chapter replaced the monastery, preserving the cathedral as an active institution within the emerging Church of England.

Civil conflict, religious change, weather, and constant use caused losses and alterations. Huguenot refugees worshipped in the crypt from the sixteenth century, adding another living community. Nineteenth-century campaigns repaired stonework and glazing, sometimes replacing decayed medieval material according to contemporary restoration ideas. German bombing in 1942 damaged the precinct and library and destroyed nearby buildings, though the main cathedral escaped the worst destruction. Modern conservation includes continuous stonemasonry and research on the exceptional medieval glass, where scientific study distinguishes original panels from later rearrangement, repair, and replacement.

Canterbury remains the cathedral of the Archbishop of Canterbury, a working place of worship governed by its dean and chapter. It forms part of a World Heritage Site with St Augustine's Abbey and St Martin's Church. The crypt, Gothic choir, pilgrimage spaces, nave, towers, tombs, and stained glass contain major original fabric, while Becket's shrine survives only through its setting, fragments, records, and modern interpretation. Sightseeing is ticketed, with worship access governed separately. The cathedral is neither a reconstruction nor an unchanged medieval monument: it is a continuously repaired institution whose architecture records mission, monasticism, pilgrimage, Reformation, conflict, and modern stewardship.