St Peter's is the finest 12thc. church in the county, and its capital sculpture is one of the highlights of the Romanesque in England. There is no structural division between nave and chancel, and the exterior treatment is uniform throughout the length of the building except for the low W tower. Nave and chancel are aisled and decorated externally at clerestorey level with blind arcading and a corbel table. Within there is no chancel arch; the division between nave and chancel being marked by a low step and the position of the choirstalls. The chancel arcades are of three bays, and both aisles are now used as vestries. In both nave and chancel the clerestorey windows are fairly regularly spaced, but their spacing is greater than a bay but less than two, so their positions vary in relation to the piers. The chancel has no provision for vaulting or roof support whereas in the nave every second pier has a respond on the nave side, running up the wall to a capital at the top, and a transverse arch respond on the aisle side. The nave aisle arches are gone now, but arch springings are sometimes visible. Intermediate piers are cylindrical. The nave arcades are five bays long (two and a half double bays), and the beginning of another bay at the W end of either arcade indicates that the nave was originally longer. It was shortened from six bays in the 17thc. when the W tower was rebuilt approximately 3m E of its original position. There are N and S nave doorways, the N under a porch.

The original tower arch was rebuilt, and shows some inaccuracies in assembly. The present tower is three storeys high with a battlemented parapet, and the western angles are buttressed by triple shafts, their diameters diminishing in stages. The middle storey is decorated with arcading and corbels, some dating from the rebuilding and some reused from the original tower or perhaps from the removed W bays of the nave clerestorey. Reset in the W wall of the tower is the arch of the original W doorway. The church is built of blocks of roughly coursed reddish sandstone (ironstone) and yellowish oolitic limestone. These are laid in decorative bands in the lower part of the tower, and there is some decorative alternation in the external blind arcading of nave and chancel, although this may not be original. Within, the lighter limestone is used throughout, except for the arches of the arcade, which use both more or less decoratively. In the 17thc. the nave was shortened by one bay, the tower being rebuilt as described above, and at the same time the original E end was demolished and a wall built across the chancel in line with the E responds of the arcade. The present E end was added by G. G. Scott in his restoration of 1850, apparently following the original foundations. Scott's E facade incorporates a central shaft with a 12thc. capital. He also rebuilt much of the clerestorey and replaced the roofs. Scott's restoration report is published in Serjeantson (1904), 259-64. In addition to the 12thc. fabric described above, St Peter's houses several loose carved stones and an important grave-slab. In 2016 it was taken into the care of the Churches Conservation Trust.

Construction of the church is usually attributed to Earl Simon II of Northampton on the basis of the style dating of the sculpture to the 1140s. The earliest reference to the church concerns the institution of a rector by deputies of Bishop Hugh of Lincoln (1186-1200), but the document makes it clear that there had been a previous rector. By the end of the 12thc. the advowson had passed to the Priory of St Andrew, Northampton.

Benefice of All Saints with St Katharine and St Peter.

Zarnecki, as ever, did the groundwork in establishing the significance of the Northampton workshop, and his guiding hand is apparent at points in the work of his student, Henry Maguire. Maguire divided the capitals into four groups, based on their decoration.

Group A (nave E responds /choir W responds N and S, choir S arcade E respond, nave N2, S2, N4, S4). Characterised by wire-like coils of grooved foliage stems with clasps, sometimes beaded. Some capitals have fictive shafts as part of their decoration; others have beasts in pairs. Maguire related these to Anglo-Saxon and Romanesque goldsmiths' work.

Group B (Choir N1, N2, S1, S2, nave W responds N and S). As A but more crudely carved.

Group C (Choir N arcade E respond, nave N1, S1). Includes Byzantine blossom and dragons with foliate tails. Maguire related these to manuscript painting.

Group D. (Nave N3, S3). Systematic and symmetrical decoration including large furled leaves with fluted lobes. He did not suggest that these represent the work of different sculptors of workshops, and to the present author it seems clear enough that the groups represent nothing more than distinctive characteristics of a single workshop, which could be combined at will.

In discussing the sources of the workshop he confined himself to two strands.An Anglo-Saxon tradition was related largely to manuscript illumination, and accounted for the prevalence of the Winchester acanthus foliage, and certain of the beast decoration. The lions on the choir N arcade E respond capital, for example, were compared with those found in a Rochester copy of Gregory's Moralia (London, BL, Royal 6.C.VI, f.91). A continued manuscript influence was detected through the appearance of the Byzantine blossom, e.g. on pier 1 of the nave S arcade. This motif he compared with initials in the Eadwine Psalter (Cambridge, Trinity College, R .17.1 e.g. on f.200v). An Anglo-Saxon tradition was also seen in the shaft-rings of the arcade piers, which he related to baluster shafts at Brixworth and Earl's Barton.

The second source examined was Northern Italian sculpture, particularly in Lombardy. Lions and dragons on imposts were compared with similar work at S.Michele in Pavia and S. Savino in Piacenza, but the most striking comparison was with the wire-like leafless foliage stems of group A, a common N Italian ornament exemplified in by the choir-rail of S. Giovanni in Pieve Trebbio, dateable c.1108.

The present author is less than convinced of the relevance of the Italian parallels, especially in view of the late date of Northampton. The wire-like foliage, for example, cannot really be separated from the ubiquitous Winchester acanthus, which had been part of the stock-in-trade of English sculpture for many decades before these capitals were carved.

Maguire's work is more useful in identifying other pieces by the same workshop. The tomb slab belongs with the capitals, employing similar Byzantine blossom, foliage, lion and dragon motifs. Nearby the fonts at Harpole, Greens Norton, Paulerspury, Dodford, Tiffield and Weedon Lois (all Northants), and Maids' Moreton (Bucks) are by the same carvers. St Chad's, Stafford, has capitals almost identical to some of those at St Peter's, but they are all 19thc. copies dating to Scott's restoration of 1873-74. They were described in the restoration report as copies of the 'lamentably abused' Norman work.

The W doorway uses a different range of motifs, based on interlaced knotwork and symmetrical flowers, and this also finds a local parallel, in the font at Mears Ashby (Northants).

As for the corbels; the replacements are fairly easy to identify, and usually seem to copy a surviving original. The originals are all in either red ironstone or yellow limestone, but there is no apparent system to this. Most are heads, some paired, including humans, monstrous forms and more-or-less recognisable animals. Of the last, a number show bears and dogs with muzzles, which is not especially common, but the usual cats and rabbits also make an appearance. The most frequently occurring beast has a lion-like head and bulging eyes, and vicious rows of teeth are a regular feature. The paired corbels are worth more study. On the N side, N52 shows a pair of bird beakheads and its neighbour, N53, has embracing male and female figures crouched to show their genitals. Among the single figures, more genitals are on display in N55 and S2.