The village of Bucknell is located in N Oxfordshire, 2.5 miles NW of Bicester. St Peter’s church comprises a chancel, central tower, clerestoried nave and a S porch. It now presents a fine example of 13thc. architecture. The central tower is its sole surviving Romanesque feature from a previous church, now flanked by a chancel and nave of the early 13thc. On the third stage, on all faces, there are rounded segmental arches over paired lights flanked by nookshafts, with a central common shaft and decorated capitals. On the N face, in addition, are two round-headed windows at different levels, one decorated with zigzag. A fourth bell stage was added to the tower in the 15thc. The tall circular stair turret on the N is also 12thc., with windows and fragments of a chevron stringcourse. Seen from the interior, the tower stood on plain Romanesque arches, those to the S and N remain with filled-in arches with small 12thc. windows under them. The E arch was rebuilt in the 14thc., but the W arch must have been modified earlier. On either side of it, to S and N at the E end of the nave, are large, blocked, round-headed arches that might previously have led to transepts. A tall 13thc. lancet window at the W end of the nave is shafted on the interior, and one capital appears to be a re-used Romanesque one with trumpet scallops.

Bucknell was one of many manors granted by William I to Robert d'Oilly of Oxford. It is possible that before the Conquest it formed part of the possessions of Wigod of Wallingford. The D'Oilly manors were eventually divided into three groups, one of which, the honor of Hook Norton, remained in the hands of the D'Oilly family. Bucknell was in this group, and its overlordship remained with the D'Oillys until the death of Henry II in 1189. At the time of the Domesday Survey, Robert d'Oilly's lands in Bucknell were assessed at 7 hides, held of him by Gilbert, who may have come from Caen and may been the same person as Gilbert de Almenceio, who also held Bletchingdon and Weston-on-the-Green in N Oxfordshire.

The earliest evidence for a church dates from 1074, when Robert D’Oilly granted tithes from Bucknell for St George's Chapel at Oxford Castle. In 1149, his son gave St George's Chapel and its revenues to his foundation at Oseney Abbey.

St Peter’s is included in the benefice of Bicester with Bucknell, Caversfield and Launton.

There is mingling of Transitional and early 13thc. motifs at Bucknell. Thus, the S nave doorway has tall slim clustered shafts on high bases, and capitals with stiffleaf, typical of 13thc. work. But it also shows relic Transitional features on the pointed arch, that is decorated with roll mouldings and a fine lattice of now-damaged free-standing chevron. The 13thc. W nave lancet window has what seems to be a re-used trumpet scallop capital.

The nave has no aisles, but at its E end it has wide round blocked arches to S and N. This suggests that these were possibly intended to open into transepts (VCH), or that the earlier church had transepts (Sherwood, 1989). However, this remains a puzzle since the axial tower provided a similar oppportunity, and there seems to be no evidence of their existence.

The church of St Ethelreda's at Horley, 16 miles NE, is of similar plan to St Peter's, and its Romanesque central tower exhibits similar paired openings to E and W on the upper stage. As at St Peter's, the tops of the openings are carved out of a single stone, but St Ethelreda's must be a little later as the arches are pointed. On the W the central capital bears corner volutes and nailhead.