Petersfield is a market town in the East Hampshire district of the county, on the E side of the A3 linking London with the S coast near Portsmouth. It stands in the Rother valley on the northern edge of the South Downs. The church is in the centre of town, on the S side of the Square, described by Pevsner (1967) as 'one of the most interesting churches in Hampshire, interesting especially because of the two phases it represents.' It was planned in the first quarter of the 12thc. as a cruciform church with a crossing tower, but of the crossing only the E arch and the E responds and capitals of the N and S arches survive. A plain window in the N wall of the nave may belong to this early phase. Above the E arch (now the chancel arch) is an elaborate composition of three tall, many-ordered windows with a single window above, which would have formed the inner E wall of the lower storey of the tower. The tower was apparently never completed, for in the mid-12thc. a low W tower was built and at the end of the century the nave was given four-bay aisles that extend far enough to the W to embrace it. The upper parts of the tower are Perpendicular.

The E walls of the nave aisle are all that remains of the transepts of the early cruciform church, and these are of flint and sandstone laid in herringbone patterns.

Romanesque features described here are the N, S and W doorways, the chancel arch, both nave arcades, the remains of the crossing tower arches, the elaborate composition (described under Windows below) that dominates the E nave wall, and the remains of an incomplete composition on the nave E gable wall (formerly the E wall of the crossing tower), including a string course and square blocks carved with simple relief designs within a triangular frame.

Petersfield is not mentioned by name in the Domesday Survey, when it was probably included with Mapledurham (now Buriton), a demesne manor belonging to the king. Before the Conquest it was held by Wulfgifu and after 1066 King William gave it to his wife Maud. When she died in 1083 it passed to the king. The manor of Mapledurham was given by William II to Robert FitzHamnon for his part in suppressing the revolt of Odo of Bayeux. He died without a legitimate male heir so the manor passed with the hand of his daughter Mabel to Robert, later Earl of Gloucester, an illegitimate son of Henry I.

The town was founded in the 12thc. by William FitzRobert, 2nd Earl of Gloucester, and was a borough by 1197. A market was granted to Richard Earl of Cornwall and his wife Countess Isabel in 1232, and a fair to be held at the manor on the feast of St Peter and St Paul was granted by Henry III to William de Clare.

The chancel was rebuilt in A. W. Blomfield's restoration of 1873-74, and he also added an inner order to the chancel arch, a N vestry and organ chamber and a clerestorey for the nave. He also rebuilt the W doorway and added battlements. The N porch was a later addition of 1887. The church was a chapelry dependent on Buriton until 1886, when it became a separate parish.

Pevsner gives 1120 as the approximate start date of the church, with the elaborate work in the triple window stage of the crossing reached c.1130-40 and the aisles including the two lateral doorways added towards the end of the 12thc. In this view, repeated by Bullen, the W tower was added before 1147, probably after the crossing tower was abandoned. The nave was thus originally built with no provision for a W tower, so the clasping side aisles may have been intended to provide extra buttressing after it was eventually built. The VCH prefers to imagine that the church was built with two towers, and that they both stood until the aisles were added, which they date c.1170-80. The VCH is the only source in the bibliography to explain the curious discrepancy in the height and width of bay 3 of the N arcade. Its pillars were resited, perhaps in 1760 when a new gallery was installed, leaving two narrow bays at the W and two wider ones at the E. They were moved again more recently to achieve a more even spacing. The remains of masonry decoration on the E wall of the nave (originally the E wall of the crossing tower) raises the interesting possibility of some kind of opus reticulatum on the tower's exterior. The stones with concave-sided squares are found in diapering on the W facade of Portchester church, and reset as fragments in the exterior N wall. The stones with diagonal crosses are similar to those in the interior spandrels of the windows above the crossing arch. They may simply have been reset after a restoration, however