St Denys Church was founded in 792AD by Duke Bertoald, who was completely healed of sickness following a visit to a monastery in Paris. The monastery had been built in memory of St Denys, a Frenchman who became the first Bishop of Paris.

Nothing remains of the original 8th century church, but the present sandstone building dates from about 1060. The oldest part of the church is the Nevill Chapel, and this is believed to have been erected in the 11th century. It is named after the Nevill branch of the Abergavenny family, Lords of the Manor from 1450. The rest of the building dates primarily from the 11th, 12th and 13th century, with later additions being the 15th century tower and porch.

The 15th century spire, damaged in the Great Storm of 1987, was replaced two years later by one of steel construction. It reaches a height of 165 feet, and is a familiar landmark for miles around. The bell chamber houses a peal of eight bells – the oldest being the Fifth which was cast in 1603.
St Denys is well known for the marvellous wall paintings which decorate large areas of the interior and date from the 13th, 14th and 15th centuries.
There is stained glass dating from the 14th century - some of the earliest known in East Sussex. The east window of the Chancel was designed by Sir Edward Burne Jones, and made in 1878 by William Morris.

The yew tree in the churchyard is said to be at least 1500 years old, which is older than the original church