The excavation of Area C1 was undertaken by the Colchester Archaeological Trust (CAT) in 2004, ahead of the development of the Garrison Alienated Land (GAL).<1><2> Area C1 comprised a 0.32ha triangular area located within the angle of Flagstaff Road and Napier Road, to the west of Flagstaff House. The site included tarmac parking and grassed areas, and a large Garrison Civil Service Club building which was demolished ahead of the archaeological investigation. An area of 292m² was excavated. The area included the remains of a short section of Roman circus, also seen on Areas C2 and J1. Other archaeological activity included a series of Late Neolithic features, three undated ditches, a post-medieval ditch, and a number of modern/military features. Six pits, dated from the mid to late Neolithic, formed a 'cluster' and appeared to represent a single phase of activity. The pits contained Peterborough ware and Mildenhall ware pottery sherds in addition to several pieces of worked flint, burnt flint and a single fragment of mammal bone. Several nearby but undated features may also belong to this period of activity. Three minor undated ditches were excavated in Area C1. One was truncated by the Roman circus and sealed by its associated Roman metalled surface. This stratigraphical relationship indicates that they were either pre-Roman or early Roman in date. Area C1 was dominated by two parallel robber trenches representing the remains of the north cavea (seating structure) of a Roman circus. They were aligned east-west and were 4.4m apart. The trenches were excavated over a distance of 12m, continuing in both directions beyond the edges of the site. Excavation showed that the northern foundation had been the wider and deeper of the two and that it had been strengthened externally by buttresses, two of which could be identified. The robber trenches contained lumps of broken mortar along with fragments of greensand and Roman brick. This material was presumably derived from the walls and foundations and must represent debris not kept by the stone robbers. A gravelled area containing fragments of Roman tile lay on the immediate north side of the cavea and butted up against the northern wall. Two parallel, east-west, shallow grooves cut the second phase of metalling. These grooves were 1.4m apart, as if they represent wheel ruts caused by Roman carts which had run across the surface. The gravelled area and the grooves were sealed by a layer of brown sandy loam rich in demolition debris in the form of fragments of crushed lumps of mortar, dated to the late 2nd to late 3rd century. Two postholes appeared to be associated with the circus, interpreted as holes for scaffolding. Three small pits of possible Roman date lay to the north of the cavea and thus were outside the circus. Another two lay within the area of the arena. The dating evidence for all five pits is limited so that, given the number of similar definite post-Roman features in the area, it is possible that some or all of these pits are also post-Roman. Other Roman activity on Area C1 consisted of seven pits, one ditch, one pit/ditch and a greensand stone spread. Four medieval features were recorded in Area C1. These features consisted of the two robber trenches (of the Roman circus), a spread of mortar and a layer of demolition. Post-medieval activity on the site is represented by nine small pits and two ditches. The modern/military features recorded on the site included five service trenches, two soakaways, one pit, one ditch and an area of disturbance. The undated features recorded on the site consisted of seven pits, one slot and one hollowed cobble path. The assessment of the excavation is presented in CAT Report 361 and the analysis in CAT Report 412. <1><2> This work followed trial-trenched evaluation; the excavation area incorporated most of trial trench C1T4 (CAT Report 271). <3>