Bodmin is a town (pop. 16,440 in 2021) in the centre of Cornwall to the SW of Bodmin Moor. The church is in the centre of the town. St Petroc's church, 151 feet long, with a tower that was 150 feet high until the spire was destroyed by lightning in 1699, is the largest parish church in Cornwall. It was rebuilt in the period 1469-1491, but the N tower is Romanesque up to the third storey, unbuttressed, with small plain windows, and strongly receding from storey to storey. Both Sedding and Pevsner agree that it was probably the N transept tower of the Norman church (viz. e.g. Blisland), which would have been the same length and height as the fifteenth century one, although with narrower aisles. The plan consists of a 6-bay nave with a 3-bay chancel, N and S aisles, a N tower sited at the junction of nave and chancel and a S porch. Construction is of local coursed and squared stone with freestone and granite dressings. The only Romanesque sculpture to have survived to the present day is the splendid font, the largest and most elaborately carved example of a type peculiar to Cornwall, although the Norman W front survived until 1814, and included a fine sculpted doorway, of which a drawing survives.

In 1086 Bodmin was held by the church of St Petroc, and while it was only assessed at 1 hide for geld, there were 68 houses and a market, consistuting a good-sized 11thc. town which became a borough in 1285. Around 1124, Augustinian canons were established in the church. Regarding the building of the Norman parish church, there is little or no historical evidence; although from the position of the N tower and the former W doorway, it can be surmised that it was much the same length and height as the present building. Sedding saw no evidence of any S transept or tower to balance those on the N side. It seems to have been considerably larger than the Priory church on the opposite side of the road, of which virtually nothing remains (Maclean).

The font is the type and finest example of the so-called Bodmin group of fonts, which includes a core set of only four by that workshop; Bodmin itself, Roche, Maker and St Newlyn East. There are at least 14 other fonts of the suspended bowl type with obvious connections to the core set, but their decoration is more simplified or almost non-existent. It is also the case that while Bodmin font gives its name to this kind of font, it cannot be the earliest of the type and this classicizing workshop is best seen as a transitional development of an older form. Thus Sedding dates the font c. 1190 (10 years after the Roche font), Zarnecki says c.1200, and Paley calls it Late-Norman or Transitional. One puzzling issue is the decoration of the upper parts of the N and E faces of the bowl, clearly intertwined serpents here, with eyes on their heads, but which at Roche appear to be cords with tassels at either end. Possibly there was some misundestanding over what was intended. Further differences with the Roche font is that the heads here are far less classicizing and they have no jewellery aroung their necks.

The description of the original W door is based on the engraving in Maclean, p. 152, which is unlikely to be accurate. Subject to this reservation, its dat appears to be the second quarter of the twelfth century. The font should be at least twenty-five years later, although probably earlier than Sedding's 'c 1190'. It is worth noting that in the nineteenth century the font "was removed by the Rev. J Wallis from the north to the south aisle (...) at the same time, it was raised on two steps of granite and cleared of many coats of whitewash"(Fryer)