Coordinates: 51°53′24″N 0°54′04″E / 51.890°N 0.901°EColchester in Essex, England, has a number of notable churches.
Excavations in the 1980s for a new police station near the Maldon Road roundabout unearthed 371 Roman graves and a long narrow building. The building was built between AD 320 and 340. Oriented east to west, an apse was added to the east end in a later phase. The building was divided by a wooden screen and two rows of posts ran down the eastern half forming aisles. The building has been interpreted on strong circumstantial evidence as an early Christian church. If this is correct, it is probably the earliest known Christian church in Britain. The remains have been preserved and are visible from the public footpath.
Dedicated to Saint Helena, the 14th-century Chronicle of Colchester states that the chapel was founded by the saint herself and refounded by Eudo Dapifer in 1076. Most of the present building dates from the 12th and 13th centuries, incorporating Roman brick. Excavations in 1981 and 1984 in Maidenburgh Street, have shown that the Roman stone and brickwork under the north and east walls were part of a theatre. In the 14th century, chantries were established in the chapel, but it was closed in 1539 after the Dissolution of St John's Abbey and it went into secular use. It became a house, a school, a library, a Quaker meeting-house and a warehouse. In the 1880s, the Round family who owned the castle, had the chapel restored by William Butterfield. After use as a clergy meeting-room and a parish hall, it was used by the Castle Museum as a store. Since 2000, it has again been used as a place of worship by the Orthodox Parish of St Helen.