Parish church. Mainly rebuilt C19 with further alterations 1932; tower and probably part of north aisle wall understood to date from 1658. West end of chancel 1693; south aisle and vestry 1822, to design of John Shaw; bapistry 1884; east end altered and enlarged 1932. Brick tower and aisles; stucco clerestory; pantiled pitched roof. Mainly Gothic revival manner. 4 bay aisled nave, 2 storey south porch, lower chancel. Square western tower of 3 stages with corner butt- resses and domed C18 clock turret. Cuspless geometrical tracery to aisle windows; clerestory with square-headed mullioned windows, each with 3 arched lights. Arcade with octagonal piers and round-headed arches, and pointed chancel-arch understood to date from 1932. Roof trusses mainly encased. Some Victorian stained glass. Various monuments mainly C17 and C18, including elaborate monuments to the Hicks family beneath the tower and monuments to William Bosanquet (1813) by John Flaxman, on west wall of north aisle, etc.
The old parish was part of the Forest of Essex. The Domesday Book records 2 priests in this area in 1086, one of who probably ministered from a church on this site. In c.1182 a church here was presented to Stratford Langthorpe Abbey and in 1327 there is a record of a vicar called Simon of Sudbury. The oldest parts of the present building date from Cromwell’s time with the tower and north aisle added in 1658; at the end of the C17th the chancel was lengthened. The oldest artefact in the church is one of its 9 bells cast by Dawe in c.1400; two of the other bells date from the C17th. Restoration work to the church was carried out in the late C18th and further changes were made in the C19th, for example by Thomas Cubitt to John Shaw’s designs, which included the south aisle and west end. The church was fully restored in 1995. It contains some interesting late C15th brasses and two monuments by John Flaxman; a monument by John Soane was demolished by vandals.
The church has an extensive graveyard in two sections, one section that surrounds the church, the other that backs onto Leyton or John Smith's Almshouses, which were first established here in 1656. The present one-storey Tudor-style building dates from 1880s designed by Richard Creed, constructed of flint and stone; it was officially opened on 9 February of that year. A path with iron railings divides the two areas of the churchyard, and the church and its churchyards are enclosed by brick walls with mature trees, long grass and many fine monuments, although many are now neglected. There are two listed monuments in the churchyard both south-west of the church tower: the monument to Benjamin Moyer, a major local landowner of the early C18th; and another C18th monument in Portland stone to Sir Fisher Tench, who built Leyton Great House, which had stood opposite the former Essex Cricket Ground (now Leyton Youth Centre q.v.). The church tower is topped by a cupola salvaged from Leyton Great House when it was demolished in the early C20th.
Among those buried in the churchyard are a long-lived soldier, William O’Brian who died in 1733 having served in the army for 60 years, and John Strype (1643-1737), who died aged 94. A famous antiquarian who wrote the lives of many great people including Archbishop of Canterbury Thomas Cranmer, Strype is also known for re-editing and enlarging John Stow’s Survey of London. He became curate and lecturer of Leyton in 1669 and in 1674 he was licensed by the Bishop of London to preach and to perform the office of priest and curate here while it was vacant, which he continued to do until his death. He built Church House nearby, but this was destroyed by bombing in WWII, when the church also suffered some damage. He is commemorated by John Strype Court, a housing development on the site of Church House. Another grave in the churchyard is that of Joseph Cotton who joined the navy at 15 and later became a director of the East India Company; he was Deputy Master of Trinity House from 1803-1825. From his travels in the east he brought back ‘a grass of remarkable fineness and strength known as Rhea or China Grass’. His son, William Cotton, was responsible for the building of Leytonstone’s parish church of St John the Baptist (q.v.).
The churchyard is now closed, and is now maintained as a nature reserve by the Friends of St Mary's Nature Reserve run by local volunteers working with Waltham Forest's Greenspace team. There are scattered trees, shrubs and tall herbs throughout the nature reserve and the site provides valuable access to nature in a part of Walthamstow that is lacking in accessible wildlife sites.