Church of St. Glies in Gileston was probably founded in the 12th century, from this period comes its nave. In the thirteenth or the fourteenth century, it was enlarged by a chancel, and in the fifteenth century, it was thoroughly reconstructed. The roof, windows and the porch were added. The church is dedicated to Saint Glies, although its dedication may also come from the local Giles family. A thorough renovation of the building was carried out in 1883, perhaps from this period the western turret comes from.
The church consists of a rectangular nave and also a rectangular chancel on the east side. A small tower is embedded in the western part of the nave. Southern, two-light windows in the nave come from the end of the 15th or the beginning of the 16th century. Both in the nave and in the chancel, there are also older ogival windows and windows topped with trefoils. The most valuable element of the church are the doors placed in the southern porch. They come from 1450 -1480 and have six carved heraldic shields and original medieval hinges. The emblems depict local families: the Walshes family from Llandough, Umfravilles from Penmark, Giles, Fleming and Cradock.
Website britishlistedbuildings.co.uk, Church of St Giles A Grade II Listed Building in St. Athan (Sain Tathan), Vale of Glamorgan.
Website coflein.gov.uk, St Glies church, Gileston