The church here was founded in the early C12th by Ralph de Toni, Lord of Walthamstow Toni Manor, on the site of a more ancient church. The area had probably been a centre of worship since Saxon times. The current church of St Mary’s is mainly C16th with later alterations carried out in 1818, 1843, 1876 and again in 1938, and the church contains many fine C17th and C18th monuments. The parish church of Walthamstow, it is situated at the centre of a surviving area of C18th and C19th development, still a residential area which retains its village atmosphere. The timber-framed Ancient House near the church probably stands on the site of the original Manor of Walthamstow; the present C15th building has been enlarged and sub-divided over the years and, converted for shops in the C19th, it was restored in 1934 for private housing once more.
The churchyard contains numerous interesting graves and four listed tombs, and is divided into four railed and enclosed areas with public access to only two; it is bisected by paths which are in frequent public use. There are some 1300 visible monuments in and around the church, and it is thought that over 26,000 burials took place here. Among those buried are Lady Penn, whose husband Sir William Penn was sent by Oliver Cromwell to capture Guiana but instead he took Jamaica. Robert Wigram is also buried here, a ship-owner of Blackwall and MP for Fowey in Cornwall and Wexford in Ireland, who rebuilt Walthamstow House in nearby Shernhall Street in 1782. He was created a baronet in 1805 and lived in Walthamstow until his death in 1830. Walthamstow House became a preparatory school in the C19th, then St Mary's Orphanage and is now Holy Family College. Monuments are densely grouped close to the west end of the church and the Monoux Almshouses (q.v.) to the north.
These almshouses together with a Grammar School for Boys were built on land acquired by George Monoux from the Prior and Vicar on 16 June 1527 so that he could build ‘houses for pore folks and the edification and building for a Schole master and a ffree scole’. Part of Monoux Almshouses were destroyed in an air raid on 8 October 1940 and were rebuilt in the 1950s; they are now private dwellings. The Grammar School on the site had closed in 1878 to be re-started with a new foundation in 1886 and a new school which opened in High Street in 1889 with accommodation for 250 boys. This in turn was taken over by Essex County Council in 1916, and again expanded, requiring larger premises. 11acres at Chapel End were purchased for the new school, which was opened in 1927 and remains today as Monoux College.
Also near the church are Squires Almshouses (q.v.), founded in 1795 by Mrs Mary Squires (d. 1796) to provide houses for 6 'decayed widows' of Walthamstow tradesmen (decayed here meaning declined in wealth), who had to be members of the Church of England and at least 50 years old to qualify - unless they suffered weak eyesight or were lame. Strict rules were laid down by Mrs Squires governing their lives, including being forbidden to hang any article in front of their house, but they were provided with coals each Christmas, a loaf of bread every Sunday and £12 a year. The picturesque single storey almshouses are almost unchanged and are fronted by a strip of cottage garden.
Chest tomb to Edward Solly (died 1776). Portland stone, Coadestone and bronze. Rectangular Portland stone plinth surmounted by Coadestone sarcophagus, supported on lionclaw feet, and decorated with lions heads and guilloche. Engraved bronze plaques.