Holywood Priory was founded by St. Laiseran before 640 on the site of the present ruins of the medieval Old Priory. The present ruins are 12th century Anglo-Norman Augustinian Abbey built by Thomas Whyte and much of these ruins remain. After the Black death (1348-1350) Niall O’Neill refurbished the church for the Franciscan Order.
The Priory was dissolved on New Years Day, 1541, by Henry VIII with its lands passing into the hands of the O’Neill family and then to Sir James Hamilton, First Viscount Clandeboye. Hamilton laid out the town, with a maypole at the crossroads and most of the early buildings are clustered round the Priory. The tower dates from the 1800’s when this was the site of the town’s Parish Church.
The adjoining burial ground has been used for centuries. Scottish settlers who arrived with the Hamilton/Montgomery Plantation in the early 17th century are buried here, though the earliest surviving gravestone is from 1645.
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.