The Romanesque abbey church was begun by Abbot Baldwin in 1081, and it thus belongs with the massive building boom that followed the Norman Conquest. Its East Anglian contemporaries were Abbot Simeon's Ely Abbey (begun c.1082) and Bishop Herbert de Losingia's Norwich Cathedral (begun 1096). The abbey church had a 4-bay eastern arm with an apsidal east end surrounded by an ambulatory with 3 radiating chapels. Like the post-Conquest church of St Augustine's Canterbury, begun by Abbot Scotland (1070-87), Baldwin's church had a large crypt underlying its eastern arm, so that the sanctuary was raised above the level of the W part of the church. This plan was well-adapted for churches that held relics and attracted large numbers of pilgrims. It allowed the shrines holding the relics to be arranged around the transept and ambulatory and the chapels opening off them, so that pilgrims could venerate the relics without entering the choir.

The eastern arm was complete by 1095 and in that year the body of St Edmund was translated to the new church. Fernie has argued that the original plan was revised to effectively lengthen the eastern arm by one bay at the W, and that this accounts for the eastern aisle of the transept, and the fact that there appear to be doubled crossing piers at the E, corresponding to the end of the eastern arm and to the line of the transept E arcade a bay to the W. It has also been argued that this lengthening of the eastern arm was a response to the details of Herbert de Losingia's ambitious plan for his new cathedral at Norwich. As part of this enlargement, the entire church was widened, so that the nave is some 14 feet wider than the chancel.

Work proceeded westwards, and the lower part of the W front was reached in the abbacy of Anselm of St Saba (1121-48), an Italian and the nephew of the Archbishop of Canterbury of the same name. Anselm of St Saba joined the monastery of Sagra di San Michele (Piedmont) as a young oblate and subsequently became Abbot of Saint Saba in Rome, serving twice as a Papal Legate (1115 and 1117) before his election to the abbacy of Bury in 1121. His connections with Sagra di San Michele, where the celebrated sculptor Nicholaus was to carve the Porto dello Zodiaco, have been suggested as a source for features of the surviving Romanesque sculpture at Bury (Zarnecki (1999)). The W front was very wide but not especially tall. The central section, corresponding to the nave and aisles had three arched recesses, similar to Lincoln cathedral. In these were set bronze doors by Master Hugo, artist of the Bury Bible (Cambridge, Corpus Christi College, MS 21). Flanking the central block were two-storey chapels dedicated to Saint Denis (below) and St Faith (above) on the N side, and to St John the Baptist and St Catherine on the S. The facade terminated at either end with an octagonal tower. Abbbot Anselm also built the Norman Tower, whose elaborate carvings give some idea of the splendid original decoration of the W front of the abbey church.

The south side of the west tower fell in 1430, and in 1431 the east side followed. The north side was demolished in 1432. A papal bull granting indulgences for the repair of the `clocher' estimated the cost of repair at 60,000 ducats. Wills of 1457-8, 1460 and 1465 provided money for the fabric of the new tower. Repair work continued until 1465, when the church was seriously damaged by a fire which started in the west tower. More extensive repair work was undertaken, and in 1506 a western spire was completed. After the Dissolution in 1539 most of the church was soon reduced to ruins. What remained of the west front was the rubble core of the three main arches flanked by a smaller arched opening on either side and with an octagonal tower at the southern end. Domestic structures were built into the dilapidated west front in the 17thc., and records show that they were altered several times in the following centuries. In 1863 the S end had become a Registrar's Residence with a Probate Registry in the S tower.

The earliest excavation of the site was by Edward King in 1772-86, and in 1865 Gordon Hills published an account of the abbey written for the British Archaeological Association's visit in the previous year. This was described by Whittingham (1952) as 'the most authoritative account of the site' then available. A documentary study of the library and the fittings was produced by M. R. James (1895). Between 1928 and 1933 a programme of clearance and restoration of the ruins was undertaken by the Bury Corporation and the Ministry of Works, and in 1952 Arthur Whittingham produced his own assessment, including a plan of the site. An excavation of the eastern arm was carried out in 1957-64 by the Ministry of Works under the direction of A. D. Saunders and M. W. Thompson of the Inspectorate of Ancient Monuments, resulting in the clearance of the eastern end of the abbey church to its original floor levels, and consolidation of the masonry (see Gilyard Beer (1970)). A programme of conservation and stone replacement was undertaken in 1999-2000, and in 2004-06 the west front was converted into a row of houses with rear gardens. A Heritage Assessment was produced in 2018 by Richard Hoggett Heritage that usefully sums up the history of investigation on the site. As part of the present investigation, access has been gained to several of the West Front properties, and we are most grateful to the residents for welcoming us into their homes.

The ruins to the east of the west front contain very little ashlar, although a few well-preserved bases of the roll and hollow chamfer type may be seen and are illustrated here. Within the west front are a few carved stones, described below, and further abbey stones are preserved at Moyses Hall, in the English Heritage store at Wrest Park, and in the British Museum (see Comments below)

Although there was a small community here from c.633, the crucial date was 903, when the remains of King Edmund, martyred by the Danes in 869, were brought to Beodricsworth (later called Bury St Edmunds) from Hoxne. The duty of guarding the shrine was entrusted to a college of four secular priests and two deacons, and in 1020 Aelfwine, Bishop of Elmham, replaced them with 20 Benedictine monks headed by Ulvius, Prior of Holme, who became the first Abbot. A new stone church was begun by King Cnut, with a generous foundation charter that exempted the abbey from episcopal control. This church was consecrated by Thelnoth, Archbishop of Canterbury, in 1032, to Christ, St Mary and St Edmund. Successive rulers confirmed and extended Cnut's gifts, and when Edward the Confessor visited in 1044 he granted the abbey the manor of Mildenhall, freedom to elect their own abbot, and jurisdiction over approximately half of the county of Suffolk. In 1065, Abbot Ulvius's successor Leofstan, died, and was succeeded by Baldwin, a monk of Saint-Denis. In the same year King Edward granted a mint to the abbey, and at this time the settlement began to be called Bury St Edmunds or St Edmundsbury rather than Beodricsworth. By the time of the Norman Conquest, Bury was ranked fourth wealthiest of all the abbeys in England and was a powerful political force, immune from interference by lay and episcopal superiors. In reponse to Bishop Arfast's petition to move his see from Elmham to Bury, Baldwin visited Pope Alexander II in Rome to obtain a Bull recognizing Bury's claim to episcopal and archiepiscopal exemption. The Pope was backed by King William, and in the face of this high level opposition, Arfast moved his see to Thetford instead.

Abbot Baldwin, with his sacrists Thurstan and Tolineus, began the replacement of Cnut's church in 1081, and in 1095, the body of St Edmund was translated to the new shrine. After the death of Abbot Baldwin in 1097 there was a series of delays in electing a suitable new abbot. Initially William Rufus prolonged the vacancy, then Henry I appointed an abbot who had not been elected by the monks. Further delays between 1102-14, and 1119-21 meant that it was not until 1121 that Abbot Anselm, builder of the remainder of the church up to the lower levels of the W front, was elected.

Meanwhile the dispute with the East Anglian see had continued following the appointment of Herbert of Losingia to the bishopric in 1191. Abbot Baldwin failed to invite the new bishop to preside at the consecration of the new church, asking Bishop Walkelin of Winchester instead. Bishop Herbert opposed the ceremony but was silenced by the recital of the papal privilege of 1072. He continued to attempt to assert his authority over Bury, however, by appropriating revenues from some of Bury's possessions, by making claims on the jurisdiction granted by King Edward, and by trying to bribe the pope (see Abou-el-Haj, 4). He also disputed Bury's claims over possession of the body of St Edmund, in favour of Hoxne, an episcopal possession. Information on the later medieval history of the abbey will be found in Victoria County History, Suffolk, ii, 56-72.

After the Dissolution the property of the abbey passed to the Crown, and in 1560 Queen Elizabeth I granted the abbey site to John Eyer. Yates (1843) pt I, 252 gives a list of Possessors of the Abbey from Eyer (1560) to Mrs Davers and Sir Charles Davers (1804). When Sir Charles died in 1806 it passed to his nephew, Frederick , Marquis of Bristol and it remained in his line until 1911, when the Borough Council leased the abbey gardens from the 4th Marquis, in order to turn it into a public park. In 1953 the Council bought the gardens outright for £7814, and in 1955 the area of the ruins was placed in the guardianship of the Ministry of Public Buildings and Works (now English Heritage).

The church itself offers very few clues to the sculptural decoration of the abbey beyond the form of the bases and the strong suspicion that at least one major arch was decorated with the chevron ornament. Sculptural fragments from the abbey church are also rare ex-situ, and in these cases there is rarely any indication of what part of the church they adorned. There are a large number of stones from the excavations of 1957-64 undertaken at the E end of the church, and they are held in the English Heritage store at Wrest Park, Hertfordshire. Unfortunately they are unsorted: most of them are simply tooled ashlar fragments, and even those with carved ornament are usually too small to allow identification of the type of object they came from. Apart from these we have a figural capital in the British Museum depicting a man battling a dragon (Zarnecki 1984, p.162) and the material in the care of St Edmundsbury Borough Council at Moyses Hall.