Today, all that remains of the Ardencaple Castle is a tower, perched on the edge of a plateau, looking down on a flat tract of land between it and the shore of the Firth of Clyde. The original castle was thought to have been built sometime in the 12th century, and part of the remains of the original castle were said to have existed in the 19th century. In 1957 most of the castle was demolished by the government in order to build naval housing for the nearby HMNB Clyde (Faslane Naval Base). Today, that sole remaining tower is used as a navigational aid for shipping on the Firth of Clyde. Because of its use as a lighthouse the tower has been called Ardencaple Castle Light.
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.