This is one of the Dengie Peninsula's two minster churches of the Christian Saxon period. The first is St Peter's Chapel founded by St Cedd at Bradwell in 654. The second church was certainly in existence by the 10th century, named "South minster" to distinguish it from St Peter's which was in effect the North Minster. The west tower of St Leonard's was built in the 14th century, propped up with a massive south west buttress. There is a decidedly unfinished look about the whole structure, topped with stone and flint battlements.