The east end was greatly enlarged at the beginning of the 12th century, and largely rebuilt in the Gothic style following a fire in 1174, with significant eastward extensions to accommodate the flow of pilgrims visiting the shrine of Thomas Becket, the archbishop who was murdered in the cathedral in 1170.

[7] In 596, Pope Gregory I ordered Augustine, the abbot of St Andrew's Benedictine Abbey in Rome, to lead the Gregorian Mission to convert the Anglo-Saxons to Christianity.

[12] The 11th-century chronicler Eadmer, who had known the Saxon cathedral as a boy, wrote that, in its arrangement, it resembled St Peter's in Rome, indicating that it was of basilican form, with an eastern apse.

He cleared the ruins and reconstructed the cathedral to a design based closely on that of the Abbey of Saint-Étienne in Caen, where he had previously been abbot, using stone brought from France.

[19] Under Lanfranc's successor Anselm, who was twice exiled from England, the responsibility for the rebuilding or improvement of the cathedral's fabric was largely left in the hands of the priors.

[20] Following the election of Prior Ernulf in 1096, Lanfranc's inadequate east end was demolished, and replaced with an eastern arm 198 feet long, doubling the length of the cathedral.

[23] William of Malmesbury wrote: "Nothing like it could be seen in England either for the light of its glass windows, the gleaming of its marble pavements, or the many-coloured paintings which led the eyes to the paneled ceiling above.

A pivotal moment in the history of the cathedral was the murder of the archbishop, Thomas Becket, in the north-west transept (also known as the Martyrdom) on Tuesday 29 December 1170, by knights of King Henry II.

In September 1174 the quire was severely damaged by fire, necessitating a major reconstruction,[24] the progress of which was recorded in detail by a monk named Gervase.

[25] The crypt survived the fire intact,[26] and it was found possible to retain the outer walls of the quire, which were increased in height by 12 feet (3.7 m) in the course of the rebuilding, but with the round-headed form of their windows left unchanged.

A marble plinth, raised on columns, supported what an early visitor, Walter of Coventry, described as "a coffin wonderfully wrought of gold and silver, and marvellously adorned with precious gems".

"[34] The income from pilgrims (such as those portrayed in Geoffrey Chaucer's Canterbury Tales) who visited Becket's shrine, which was regarded as a place of healing, largely paid for the subsequent rebuilding of the cathedral and its associated buildings.

[35] A bird's-eye view of the cathedral and its monastic buildings, made in about 1165[37] and known as the "waterworks plan" is preserved in the Eadwine Psalter in the library of Trinity College, Cambridge.

[36]: 158–181 [39] It shows that Canterbury employed the same general principles of arrangement common to all Benedictine monasteries, although, unusually, the cloister and monastic buildings were to the north, rather than the south of the church.

To the north, a large open court divided the monastic buildings from menial ones, such as the stables, granaries, barn, bakehouse, brewhouse, and laundries, inhabited by the lay servants of the establishment.

The prior's group were "entered at the south-east angle of the green court, placed near the most sacred part of the cathedral, as befitting the distinguished ecclesiastics or nobility who were assigned to him."

[44] From the late 14th century the nave and transepts were rebuilt, on the Norman foundations in the Perpendicular style under the direction of the noted master mason Henry Yevele.

[45] In contrast to the contemporary rebuilding of the nave at Winchester, where much of the existing fabric was retained and remodeled, the piers were entirely removed, and replaced with less bulky Gothic ones, and the old aisle walls were completely taken down except for a low "plinth" left on the south side.

There are currently 53 statues representing various figures who have been influential in the life of the cathedral and the English church such as clergy, members of the royal family, saints, and theologians.

Mounted on the wall above it, there is a metal sculpture by Truro sculptor Giles Blomfield depicting a cross flanked by two bloodstained swords which, together with the shadows they cast, represent the four knights who killed Becket.

The last quinquennial structural review[70] revealed that a combination of centuries of weathering, pollution and constant use had taken its toll on the ancient building and some serious problems were in need of urgent action.

The head of the cathedral is the Dean, currently David Monteith, who is assisted by a chapter of 30 canons, four of whom are residentiary, the others being honorary appointments of senior clergy in the diocese.

The Foundation also includes the choristers, lay clerks, organists, King's Scholars, the Six Preachers and a range of other officers; some of these posts are moribund, such as that of the cathedral barber.

Fundraising for the appeal will take place over a number of years both nationally and internationally, stressing the cathedral's role as the mother church of the worldwide Anglican Communion and as a World Heritage Site.

Improvements are planned to the fabric of the library buildings and to the cathedral's audio-visual and lighting systems which will significantly benefit visitors including the disabled, visually impaired and hard of hearing.

The appeal also aims to develop the outmoded workshop area and stained glass studio, in order to ensure the survival of Canterbury as a centre of excellence for vital craft skills and to promote a sustainable maintenance base for work on the cathedral which can be viewed by the public.

The fundraising group is the Canterbury Cathedral Trust, an independent, registered charity (1112590) seeking funds to provide conservation, craftsmanship, music and education.

The Girls' Choir of Canterbury Cathedral was founded in 2014 and their first performance at Evensong, in January, was attended by more than 600 people and widely covered by the international press.

[117] In February 2023 it was announced that the entire framework for the child choristers at Canterbury Cathedral would be changing and that they would no longer board or attend St Edmund's School, causing local and international comment.

[123] The cathedral also has custody of the bell of HMS Canterbury, a World War I-era light cruiser, hung near the Buffs Chapel in the southwest transept.