St Helens Church, Mareham le Fen, is mainly of the Decorated (about 1290 to about 1350) period with some Early English (13th century) and Perpendicular (about 1335 to 1350 to about 1530) work. The church was heavily restored in 1879. {1}{2}{3} A church and a priest are mentioned in the Domesday Book. {4} A parish church dating from the late 13th century which underwent alterations in the early 14th, late 14th, 15th and 16th centuries. In 1879 the exterior was partially rebuilt and in 1974 the vestry was extended. For the full description and the legal address of this listed building please refer to the appropriate List of Buildings of Special Architectural or Historic Interest. {5}