This cruciform church of limestone rubble stands high above the west bank of the Cherwell, 8 miles north of Oxford. It now comprises the chancel, built up due to the sloping ground, central tower, N and S transepts, and a clerestoried nave with a S aisle. The N and S walls of the nave may be partly pre-Conquest. Although it was probably originally aisleless, on the N side remain two blocked arches, visible both on the outside and inside walls. These may represent either porticus arches, or arches of a N arcade built c. 1120. Whatever their nature, the extensions were demolished in the early C13th.

A similar situation may have pertained on the S side because the S arcade and aisle were also built or rebuilt at the time of the demolition, when also the chancel was extended eastwards and the nave westwards. The N nave doorway of c. 1120 is thought to have been reset within the NW blocked nave arch also at the same time. The arch of another early Romanesque doorway, decorated with roll mouldings, is now set in the E wall of the churchyard. On the nave interior there are small round-headed arches, one each on N and S walls, just below the clerestorey windows. The W bay of the chancel on the S side still retains a C12th pilaster buttress. A further Romanesque detail is the three beakheads reset on the S face of the second stage of the tower.

There is some archaeological evidence to suggest that the church existed in the Anglo-Saxon era. Before the Conquest, Tackley was held by Hugh or Hugolin, Edward the Confessor’s chamberlain. By 1086 the overlordship had been granted to Hugh d'Avranches, Earl of Chester, who gave the church with its glebe and tithes to the Abbey of St Sever (Vau de Vire, diocese of Coutances), that he had founded. It was confirmed by the pope in 1158, but by 1200 the advowson had reverted to the lords of the manor. The overlordship descended with the earldom until 1232, when it passed to Hugh d'Aubigny, earl of Sussex and Arundel.

If the church had portici, then they were probably built in Earl Hugh’s time in the late C11th. This was unusual for an ordinary church, unless he hoped it would attain minster status, as at Brixworth in Northamptonshire. The VCH suggests that the Saxon church may have had portici on both sides of the nave. On the S side, with a C13th. aisle, there seems to be no evidence of previous structures. The simplest explanation for the N arches is that of Sherwood and Pevsner (1974) who consider them to be a previous arcade. They point out that the length of the space between them suggests that they stood on rectangular masonry piers, and that the quality of the workmanship (rough masonry, lacking competence) suggests that it was of C11th origin.

Sherwood and Pevsner’s assertion that the reset N doorway is of late C12th date is not so plausible. It has to be considered together with the other C12th doorway mounted in the churchyard wall. Both the doorways are of the same width, as defined by the width of the arch, which is possibly significant. Unfortunately their heights are not comparable as the jambstones have been replaced. As both are of simple style, they probably date from a similar earlier time, c.1120, as suggested by the VCH.

The original location of the three reset beakheads is also unknown. The heads are grotesque, not bird-like. Although they lack beaks, they overlap a roll moulding, suggesting they were once sited over an arch. The VCH refers to them as corbels, although it is difficult to ascertain the exact shape of the blocks. The date of carving would appear to be c. 1140-70, but their particular style does not link them to any other known beakheads in Oxfordshire (Newson, 2013).