St Thomas à Becket Chapel was constructed in 1180 and dedicated to St Thomas Becket. It commanded fine views of the Haven estuary, situated on the north bank in open space. Along with two other chapels, now disappeared, at Herbrandston and St Anne's Head, it functioned not only as a Catholic place of worship, but also as a Beacon Chapel, or lighthouse to sailors. The chapel enjoyed a dependent relationship with the nearby Pill Priory. By the 17th century the structure was in ruins, when it was occupied by Parliamentarian forces in 1644. It later acquired a function as storage for the battery located on the Rath.
In the twentieth century, it had become used as a pigsty and stable. In 1930, £1,000 was raised, and the building was reconstructed, work completed in 1938. It was re-consecrated as an Anglican chapel of ease. It is built of rubble stone with a graded slate roof, small nave and chancel, both with pointed barrel vaults. The interior is simple with plastered vaults, small niches each side in chancel and a curved rood beam with rood. The nave south facing windows have stained glass of 1935 and 1939 to Sir Hugh Thomas of Castle Hall. In 2012 it was privately sold, in spite of local opposition.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.