Monument record TR 15 NW 2741 - Roman features at St Mildred's Tannery, Canterbury

Summary

Archaeological investigations at St Mildred’s Tannery in Canterbury have revealed a rich concentration of Roman features. Excavations uncovered a large Roman building, possibly a mansio, near Watling Street and the London Gate, with evidence of multiple construction phases. Early structures were timber-framed with clay walls, later replaced by masonry buildings with courtyards, porticos, and raised floors. A Roman street with gravel metalling and drainage features was identified, along with associated buildings, hearths, and courtyards. Environmental assessments indicated wet conditions and reed swamp development towards the end of the Roman period, contributing to the abandonment of structures due to rising water tables. Finds included tile, mortar, charcoal, oyster shell, and pottery. Additional discoveries included a probable riverside hard, rampart deposits, and domestic refuse layers. A timber-lined well and brushwood trackways were also found, possibly dating to the Roman or Anglo-Saxon periods. These features suggest a complex and evolving urban landscape, with Roman infrastructure adapted to environmental changes and later reused or repurposed in subsequent periods. The site’s proximity to major Roman roads and gates underscores its strategic and functional importance during the Roman occupation of Canterbury

Location

Grid reference Centred TR 1451 5768 (229m by 201m)
Map sheet TR15NW
County KENT
District CANTERBURY, KENT
Civil Parish CANTERBURY, CANTERBURY, KENT

Map

Type and Period (11)

Full Description

Since 1997 the site of the former St Mildred's Tannery has been subject to extensive archaeological investigation and has revealed a siginficiant concentration of Roman, Saxon, Medieval and later discoveries.

Archaeological investigations at St Mildred’s Tannery in Canterbury have revealed a rich concentration of Roman features. Excavations uncovered a large Roman building, possibly a mansio, near Watling Street and the London Gate, with evidence of multiple construction phases. Early structures were timber-framed with clay walls, later replaced by masonry buildings with courtyards, porticos, and raised floors. A Roman street with gravel metalling and drainage features was identified, along with associated buildings, hearths, and courtyards. Environmental assessments indicated wet conditions and reed swamp development towards the end of the Roman period, contributing to the abandonment of structures due to rising water tables. Finds included tile, mortar, charcoal, oyster shell, and pottery. Additional discoveries included a probable riverside hard, rampart deposits, and domestic refuse layers. A timber-lined well and brushwood trackways were also found, possibly dating to the Roman or Anglo-Saxon periods. These features suggest a complex and evolving urban landscape, with Roman infrastructure adapted to environmental changes and later reused or repurposed in subsequent periods. The site’s proximity to major Roman roads and gates underscores its strategic and functional importance during the Roman occupation of Canterbury

1987 – Initial Excavation (TAN87)
Conducted by Canterbury Archaeological Trust within the allotments adjacent to the tannery.
Revealed three phases of a Roman structure, including timber and masonry buildings, a courtyard, and evidence of abandonment by the 4th century.
Early medieval stake holes were found, possibly linked to animal husbandry (1,2)

1991–1992 – Site Evaluation
A trench excavated in 1991 uncovered a Roman metalled street aligned northeast to southwest, likely draining into a sewer or the River Stour. The road had been resurfaced multiple times and featured a raised lip on its western edge

To the west of the street, remains of a Roman building were identified. These included:

A portico with a floor constructed from broken tiles, opus signinum, and mortar.
A substantial masonry wall footing interpreted as the opposite side of the portico.
A clay-floored room with a beam scar and post-holes, possibly from scaffolding.
A roughly metalled courtyard and a second portico or corridor with a mortared floor
The building was likely abandoned in the late Roman period due to a rising water table. Its materials were largely removed, and the site was later covered by humus-rich soil and peat, followed by dark loam containing wooden stakes and posts—interpreted as evidence of medieval cultivation
Additional trenches near the Riverside Walk exposed walls possibly linked to the city wall or early tannery structures, though no dating evidence was recovered.(3, 4)

2001 – Desk-Based Assessment and Major Evaluation
A desk-based assessment was carried out in January 2001 to assess archaeological potential ahead of development.
From May to July 2001, a large-scale evaluation involved 27 trenches and several sondages.

Buildings and Infrastructure: Well-preserved Roman buildings were uncovered, including structures with clay floors, opus signinum surfaces, and mortared flint walls. These were often associated with metalled streets and courtyards
Street Systems: Several gravel-metalled Roman roads were identified, some possibly merging into riverside hards. These roads showed signs of repeated resurfacing and drainage adaptations
Environmental Evidence: Environmental sampling revealed that by the late Roman period, the area had become increasingly waterlogged. Reed swamp conditions developed, likely contributing to the abandonment of buildings (5)

2002 – Watching Brief
Boreholes and auger probes were used to monitor development impacts.
Roman streets, buildings, and river-related features were identified, along with Anglo-Saxon and medieval layers

Street Metallings and Surfaces: Extensive metalled surfaces were identified across the site, interpreted as Roman streets, floors, yards, and courtyards
Structural Elements: A mortared flint and tile wall, scorched clay floors, and preserved reed linings were found, indicating well-preserved Roman building remains
Environmental Layers: Layers of Roman river silts and domestic refuse were uncovered. These included oyster-rich gravel and deposits containing charcoal, shell, pottery, and tile
Rampart and River Features: Deposits interpreted as part of the Roman rampart and a probable riverside hard were identified, along with berm material and a Roman-period riverbed (6)

2006–2007 – Phase 2B Evaluation
Focused on Blocks G–I of the development.

Roman Architectural Features: A small room with an apsidal (semi-circular) end and an external flue or drain was discovered near previously excavated Roman structures from 1987. These features, along with nearby walls and deposits, suggest the presence of a hypocaust system, likely part of a Roman bath suite 1.

Urban Layout Revisions: The evaluation revised earlier interpretations of the Roman street layout. A previously posited street continuation from Black Griffin Lane was discounted, and the boundary between built-up areas and marshland was found to extend farther southwest than previously thought

Courtyard Complex: The area between the apsidal room and a possible large aisled building (beneath Blocks C–E) was likely a large gravelled courtyard, suggesting a unified architectural complex

Town Wall and Gateways: The Roman and medieval town wall was examined using both intrusive and non-intrusive methods. A narrow Roman gateway, possibly with a bridge abutment, was found near Block L. This was later replaced by a wider medieval gateway (possibly the Halistane Gate), and the wall was diverted to form a re-entrant near the river

Post-Roman Layers: Boreholes revealed a sequence of disturbed loams, metalling, and turf lines over peat, interpreted as early medieval dumping and cultivation over former marshland (7)

Geophysical Surveys (1987, 2006)
Various techniques including resistivity, magnetometry, and ground-penetrating radar were used.
Results were mixed: some features were identified, but others were obscured by overburden or modern disturbance (8, 9)


Canterbury Archaeological Trust, 2002, St Mildred's Tannery, Stour Street, Canterbury: Second Archaeological Watching Brief on Geo-Technical Augering (Unpublished document). SKE56084.

<1> Blockley, P., 1987, The Tannery (Article in serial). SKE30413.

<2> Canterbury Archaeological Trust, 2001, St Mildred's Tannery Stour Street, Archaeological Desk Assessment (Unpublished document). SKE30412.

<3> Canterbury Archaeological Trust, 1992, St Mildred's Tannery Site, Canterbury Evaluation 1991- 1992 (Unpublished document). SKE7976.

<4> Pratt, S., 2000, Tannery Evaluation Trench: Proposed Supermarket Site (Unpublished document). SKE30637.

<5> Canterbury Archaeological Trust, 2001, St Mildred's Tannery, Stour Street, Canterbury: Archaeological Evaluation (Unpublished document). SKE58539.

<6> Canterbury Archaeological Trust, 2002, St Mildred's Tannery, Stour Street, Canterbury: Second Archaeological Watching Brief on Geo-Technical Augering (Unpublished document). SKE56084.

<7> Canterbury Archaeological Trust, 2008, Archaeological Evaluation report of land at St. Mildred's Tannery, Stour Street, Canterbury (Unpublished document). SKE52094.

<8> Linklater, A., 2001, Andrew Linklater pers comm (Verbal communication). SKE30414.

<9> Canterbury Archaeological Trust, 2006, St Mildred's Tannery, Canterbury: Phase 2B Geophysical Survey (Unpublished document). SKE51916.

Sources/Archives (10)

  • --- Unpublished document: Canterbury Archaeological Trust. 2002. St Mildred's Tannery, Stour Street, Canterbury: Second Archaeological Watching Brief on Geo-Technical Augering.
  • <1> Article in serial: Blockley, P.. 1987. The Tannery.
  • <2> Unpublished document: Canterbury Archaeological Trust. 2001. St Mildred's Tannery Stour Street, Archaeological Desk Assessment.
  • <3> Unpublished document: Canterbury Archaeological Trust. 1992. St Mildred's Tannery Site, Canterbury Evaluation 1991- 1992.
  • <4> Unpublished document: Pratt, S.. 2000. Tannery Evaluation Trench: Proposed Supermarket Site.
  • <5> Unpublished document: Canterbury Archaeological Trust. 2001. St Mildred's Tannery, Stour Street, Canterbury: Archaeological Evaluation.
  • <6> Unpublished document: Canterbury Archaeological Trust. 2002. St Mildred's Tannery, Stour Street, Canterbury: Second Archaeological Watching Brief on Geo-Technical Augering.
  • <7> Unpublished document: Canterbury Archaeological Trust. 2008. Archaeological Evaluation report of land at St. Mildred's Tannery, Stour Street, Canterbury.
  • <8> Verbal communication: Linklater, A.. 2001. Andrew Linklater pers comm.
  • <9> Unpublished document: Canterbury Archaeological Trust. 2006. St Mildred's Tannery, Canterbury: Phase 2B Geophysical Survey.

Finds (5)

Protected Status/Designation

  • None recorded

Related Monuments/Buildings (0)

Related Events/Activities (11)

  • Intrusive Event: Archaeological evaluation at St Mildred's Tannery, 2001 (EKE25006)
  • Intrusive Event: Archaeological evaluation, St Mildred's Tannery, 2006/7 (Ref: TAN 05-07) (EKE19688)
  • Intrusive Event: Archaeological watching brief at St Mildred's Tannery, Stour Street, Canterbury, 2002 (Ref: Site code: TAN02WB2) (EKE23149)
  • Intrusive Event: Canterbury CCTV VMS masts, Archaeological Watching Brief and Windowless Sampling (Rheims Way) (Ref: 2012/212) (EKE16736)
  • Intrusive Event: Evaluation at Tannery Riverside Walk Site, Canterbury (EKE5847)
  • Intrusive Event: Excavation at The Tannery Allotments, 1987 (Ref: CAT: 115 / Site code: TAN87) (EKE13738)
  • Non-Intrusive Event: Phase 2B Geophysical survey, St Mildred's Tannery, Trench Survey, 2006 (Ref: TAN06/EV4) (EKE19633)
  • Non-Intrusive Event: Phase 2B Geophysical survey, St Mildred's Tannery: allotment site, 2006 (Ref: TAN06/EV4) (EKE19632)
  • Intrusive Event: St. Mildred's Tannery Site Evaluation 1991-2 (EKE5846)
  • Non-Intrusive Event: Tannery Allotment Gardens (Ref: CAT: 115) (EKE13739)
  • Intrusive Event: Watching brief on EDF trenching, test-pits and moling, 2007-8 (Ref: Project Codes: TAN 07 WB24 & TAN 08 WB48) (EKE19830)

Record last edited

Jul 21 2025 11:19AM