The large parish church of St Peter is located at the N end of High Street. Built of flint with ashlar dressings and tiled roofs, it comprises a chancel, a four-bay aisled nave, a S porch and a NW vestry. A tower stands at the W end of the S aisle.

A mortar has been brought into use as a font and loose stones are stored by the pulpit.

Bishop's Waltham was held by the bishops of Winchester from most of the period between 904 and 1551. After several years in secular hands, it was returned by Queen Mary.

Henry of Blois, bishop from 1129 until his death in 1171, built a palace at the S end of the town. The site, now managed by English Heritage, was greatly enlarged over the centuries (notably by Bishop William of Wykeham in the late 14thc. and early 15thc.) but ruined in the Civil War.

In 1086 the parish church was held by Ralf the priest. Henry of Blois is said to have moved the church to its present site (Riall 1994, 10). He granted the advowson to the Hospital of St Cross, founded outside Winchester c.1136, but it reverted to the bishop in the 13thc. The nave aisles were probably added under the auspices of St Cross. Although the stonework has been largely renewed, the early 13thc. N arcade appears to be the oldest surviving part of the church.

The entire building has been heavily reworked, repeatedly, since the Dissolution. The tower collapsed in 1582 and was rebuilt in 1584-89. The N aisle was rebuilt in 1637 and the S aisle in 1652. The nave roof was reconstructed in 1669. A W gallery, for an organ, was installed in 1733. In 1798 the S arcade was destroyed to make way for a S gallery. The first 19thc. restoration campaign took place in 1849, when the W end of the nave was rebuilt. Other restorations were undertaken in 1864-68 and 1894-97. In 1894-97, under the architect T. G. Jackson, the columns of the N arcade were replaced, the S arcade was rebuilt and the chancel arch was repaired.

The mortar currently used as a font was found in a garden in Houchin Street in 1933 and brought into the church. In 1944 it was stored with the scallop capital and pillar piscina shaft beside the pulpit (Historic England Archive, red boxes). By 2025 it had been brought into use as a font. Its predecessor was presumably the font gifted to the church in 1904, which was described by the VCH as modern, with ‘a square bowl worked with shallow tracery patterns’ (VCH 1908, 280). The pre-1904 font was described as ‘small and insignificant’ (Hampshire Chronicle, 16 April 1904, 7).

The VCH made the reasonable suggestion that the loose scallop capital came from the S arcade, which was dismantled in 1798. It may be surmised that this arcade dated from the late 12thc. and slightly preceded the early 13thc. N arcade.

The mortar/font is thought to be an ancient font, possibly of Saxon date (Historic England, list description). It may, however, simply be a mortar of indeterminate (but probably medieval) date. Large mortars of this type were often associated with large households, including monastic houses. This example may have come from the Bishop’s Palace.