In 2015-2017, Colchester Archaeological Trust undertook the ‘Stage 2 and 3’ archaeological mitigation investigations on restricted impact locations at Colchester Garrison Alienated Land (GAL) Area B1b (previously known as Flagstaff House, now known as Arena Place) of Taylor Wimpey’s wider Colchester Garrison Alienated Land development, i.e. every effort was made to minimise the impact of the development on below-ground archaeological remains. The investigations consisted of archaeological evaluation (ECC2913) and excavation (seven areas totalling 2,542 square metres) followed by monitoring of groundworks during the construction phase (ECC2911).<1><4> The main excavation areas comprised: Areas A and B located over the area of the Roman Circus (A was over the line of the central barrier and B was over the line of the cavea), and Area C, West Building, Sewer Trench and White Building (following the domolition of Building Blocks 4 and 5) located within the area of the precinct of St John's Abbey. The work followed two stages of trial-trenched evaluation, ECC2553 in 2002 and ECC2803 in 2007.<2><3> No contexts of prehistoric date were on GAL Area B1b. The small assemblage of residual prehistoric pottery and worked flint is likely associated, the report suggests, with Neolithic and Bronze Age pits identified in close proximity in GAL Areas A1, C1, C2, J1 and Flagstaff Road. The evaluation trenches T1 and T2 (see ECC2913) and excavation Areas A and B were specifically targeted over the circus. The aim of most of these investigations was to establish maximum dig-depths for the development to preserve as much of this important monument in situ as possible. As a consequence, few of the features directly associated with the circus were excavated, aside from those in Area A which were located on a major service line and not possible to avoid. Approximately 17m of robber trench over the outer cavea wall was exposed during the current project, which included one buttress in Area B. Although excavation was limited, no in situ wall foundations were apparent. In contrast, only 7m of robber trench over the inner cavea wall was exposed but a small section of in situ wall foundation to the east of Block H had survived. At 0.7m wide and made of fragments of greensand stone set in a yellow mortar, this surviving section of inner cavea is comparable to other surviving sections elsewhere along the length of the circus. The large pit (AF166) located in the centre of the barrier was of similar shape and dimensions to the probable water tanks/cisterns at the western end. All three pits included fragments of painted opus signinum in the backfill, perhaps used as a waterproof lining. Although no iron water collars were found in Area A, a gully (AF164) did appear to drain into the pit providing further evidence for its use as a water tank. A robber trench (AF165) on the northern edge of Area A is probably part of the perimeter wall of the central barrier; it was, however, much larger than seen elsewhere. Two small patches of buried topsoil identified immediately to the south of the inner cavea in excavation Area B (BL52) and during monitoring in Block H (WBL199) area probably parts of the arena surface. A medieval pottery sherd of late 11th- to 12th-century date and fragments of peg-tile were recovered from robber trenches and layers of demolition, along with Roman finds including pottery, ceramic building material and building stone. This would indicate that the final phase of robbing of the circus structure dated to at least the 13th/14th century. In addition to the circus, seven pits in Area B (BF156, BF159/WBF442), Area C (CF277, CF280, CF311) and the White Building (WBF220, WBF267) probably date to the 2nd century. The majority of these features were quite large and were possibly dug as quarry pits for sand and gravel used in the construction of the circus. Pit BF159/ WBF442 was particularly interesting as it had been backfilled with a large quantity of southern Gaulish plain and decorated samian included in the assemblage. Eleven pits in Area B (BF140), Area C (CF303, CF333), the West Building (WBF352, WBF357 with postholes WBF361-3, WBF359, WBF368), White Building (WBF247) and recorded during monitoring (WBF434, WBF477, WBF481) dated from the 3rd to the 4th century, probably to the period after the circus was no longer in use (c.AD 275). It is likely that these too were quarry pits, with substantial amounts of waste being used to backfill them. In Area C, a large quantity of residual Roman material came from features that were demonstrably from a phase of medieval activity. Only one Roman inhumation burial (WBF524) was present within GAL Area B1b. The burial, dating from the late 3rd-century, had been buried within a wooden coffin with four pottery vessels, a copper-alloy bracelet and probable earring. One of the vessels, a small dish, contained the articulated knee joint of a pig and a small rack of ribs. Also within this grave were the truncated remains of the urned cremation of an adult. Approximately 16.5m of surviving in situ foundation from the precinct wall of St John's Abbey was revealed in excavation Area A and during monitoring around Block A, constituting part of the southern east/west wall. The foundation was 0.8m wide and was made of septaria, greensand stone and reused Roman ceramic building material set into a lime-mortar, similar to that seen in 1972 when part of the standing wall was demolished (CAR 9, 219). Between Area A and Block A, a short stretch (c 9m) of precinct wall survives built into the southern wall of Block F (a garrison wagon shed dated to the late 19th century). In 2016, as part of the current redevelopment, the wall was surveyed and conserved. The exact alignment of the precinct wall in the southwest corner remains uncertain. In terms of associated buuildings and strcutures within the abbey precinct, in Area C, a structural feature was encountered in the base of an area of quarry pitting associated with postholes, a gully and layers of compacted clay. A lace tag compressed into the top of a clay layer shows that it was in use by c.1375 to 1550/75. The remains of a medieval clay oven were also found in a service trench to the east of Block A. The oven was probably dome-shaped and sub-divided into two compartments. No dating evidence was recovered but it had been built against the inside of the precinct wall and must post-date the construction of the wall. Two small sections of wall foundation were found in monitoring trenches in the north/south access road and to the north of Block A. Of probable medieval date they could represent the remains of internal structures but neither could be properly excavated or explored. The current project also revealed a further three lime kilns around the area of the White Building and Block O (in addition to three lime kilns already recorded within St John's Abbey precinct). All six of the lime kilns now known from St John's Abbey precinct were round features with scorched edges measuring between 4-7.5m in diameter with two recorded at 1.7m and 2.15m deep. The quarry pits in Area C are likely to be contemporary with the lime kilns as they would have provided sand and gravel for construction. The remains of the possible temporary structure/workshop in the base of the pits would provide further evidence that this was a working area of the precinct. It is possible that two parallel ditches in the White Building continue northwards in Area C and towards the abbey gatehouse forming a trackway through the precinct. Most of the medieval ditches are concentrated to the west of this possible trackway and may have created defined plots; dating evidence suggested that most of the ditches had either been backfilled or were not being maintained by the 14th/15th century. A partial wall foundation to the west of Block 1 could be associated with Lucas House or its ancillary buildings. Wall foundations and a hearth/oven in evaluation trench T3 to the north of the development site represent the remains of another post-medieval structure/building. The remains of modern brick and concrete wall foundations were recorded across GAL Area B1b. Most correspond to garrison buildings built in the late 19th and 20th centuries.