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The Roman Circus and St John's Abbey: Stage 2 and 3 archaeological mitigation investigations on Colchester Garrison 'Alienated Land' Area B1b, off Napier Road, Colchester, Essex, CO2 7NU: July 2015 – October 2017
by Laura Pooley
(with contributions from Mark Baister, Stephen Benfield, Philip Crummy, Julie Curl, David Dungworth, Val Fryer, Emma Holloway, Dr Matthew Loughton, Rob Masefield, Alec Wade and Adam Wightman)
Date report completed: 2019
Location: Colchester
Map reference(s): TL 99708 224605 (centre)
File size: 119,162 KB kb
Project type: Evaluation, excavation & monitoring
Significance of the results: Significant
Keywords: Roman circus, St John's Abbey, Colchester Garrison
Summary. In 2015-2017 Colchester Archaeological Trust completed the ‘Stage 2 and 3’ archaeological mitigation investigations on restricted impact locations at Colchester Garrison Alienated Land Area B1b of Taylor Wimpey’s wider Colchester Garrison Alienated Land development. The investigations consisted of archaeological evaluation (three trenches totalling 105 square metres) and excavation (seven excavation areas totalling 2,542 square metres) followed by several months of monitoring of groundworks during the construction phase.Colchester Garrison Alienated Land (GAL) Area B1b is located within two nationally significant scheduled monument zones. The first monument is Britain's only known Britain circus (SM 1021426). Orientated east to west, c 450m long by 71-74m wide and used for chariot racing, approximately 0.8 hectares of the circus is located along the southern edge of GAL Area B1b. The second monument is St John's Abbey (SM 1015015). Parts of the abbey precinct wall still survives along with the magnificent abbey gatehouse (listed building 1337765) and the demolished abbey church stood within GAL Area B2 to the northeast. GAL Area B1b is located within the southwestern corner of the abbey precinct.
Specific locations over the Roman circus were targeted for investigation in GAL Area B1b. Medieval robber trenches associated with the cavea wall foundations and central barrier were the dominant type of feature uncovered: 17m of robber trench over the outer foundation of the cavea; 7m of robber trench over the inner foundation of the cavea, which included a small section of surviving in situ wall foundation; and 4m of robber trench over part of the perimeter wall of the central barrier. Excavation of the central barrier revealed evidence for a lined water tank and associated drainage ditch, and small sections of the dirt racetrack had survived.
Other Roman features included a small number of pits and quarry pits, dating to the 2nd century and the 3rd to 4th century. To the northeast of the circus was a late 3rd-century inhumation burial which had truncated an earlier urned cremation burial.
Approximately 16.5m of surviving in situ foundation from the precinct wall of St John's Abbey was revealed during the investigations. At 0.8m wide it was made of septaria, greensand stone and reused Roman ceramic building material set into a lime-mortar. Evidence for internal structural remains within GAL Area B1b and the southwestern corner of the abbey precinct was scarce with evidence of a possible temporary workshop, a clay oven and a two small sections of wall foundation. Four lime kilns were found during groundworks, taking the total number of lime kilns known from St John's Abbey precinct to six. Five of the six kilns were clustered along the western edge of the precinct and appear to date to a period of rebuilding after a devastating fire in AD 1133. Quarry pits for sand and gravel were probably contemporary with the kilns and provided raw materials for construction. A possible trackway ran through the development site and numerous ditches appear to define plots for small-scale agricultural activities and animal husbandry for the abbey. The lack of substantial structural remains together with the presence of lime kilns, quarry pits and ditches, would suggest that this corner of the abbey precinct was largely kept as open ground.
Other structural remains in GAL Area B1b included a post-medieval building/structure on the far northern edge of the development site, a post-medieval stone boundary wall built around later orchards, and modern foundations from demolished garrison buildings. Post-medieval and modern pits and postholes were also found scattered across the development site.