Whilst ordinary residents of the southern East & West Hyde might have found St Peter, Harpenden a more convenient place of worship, until the establishment of Holy Trinity as a separate parish, the area fell within the Parish of Luton.

Chancel looking towards the Wenlock Chapel

Visually cut off by encircling roads and stark University buildings, this jewel deserves a more sympathetic setting. Inside, the historical significance of this church is underlined by panels on the wall of the South Aisle bearing a roll of vicars since 1050.
Whilst over the centuries, the national institution we refer to as "The Church" of the time has been powerful and independent of any except the monarch, the local church has been much influenced by the patronage of wealthy landowners. This has been reflected in parish boundaries and the structures of the church buildings. St Mary has a number of memorials to past leading figures of the local communities as well as the Wenlock and Hoo Chapels.

Not all the fine features of the building are centuries old, The Magnificat Window installed in 1979 is spectacular.
The church has stood on its present site since 1137, commissioned by Robert, Earl of Gloucester who dedicated it to St Mary. The building replaced one, constructed originally under instructions of King Edward, which was completed by his successor, Ethelstan and consecrated in 931.
However its history extends further back to around 673 and foundation by Wulfhere.
Accounts of early administration vary. Luton may originally have fallen within the Diocese of Dorchester in Oxfordshire when Bedford came within the kingdom of Mercia.
Bishoprics were reorganised periodically. Luton may have become part of the Diocese of Leicester, but certainly when Llanfranc, Norman Archbishop of Canterbury undertook an exercise (recognising the changing status of communities) to move responsibilities to more important towns Bedfordshire came within the Diocese of Lincoln from 1075.
The local responsibility and income of the church fell to St Albans Abbey from the late 8th to late 9th Century and again from the 12th Century until dissolution of St Albans in 1539.

The Wenlock Chapel

The Diocese area was divided in 1542, but remained large.
In 1837, the Archdeaconry of Bedfordshire became part of the Diocese of Ely.
The earlier association with the Abbey was renewed when St Mary’s became a part of the Diocese of St Albans in 1914.