The Ruins of the Cross Kirk can be found just north of the town centre of Peebles. The ruins were once a Trinitarian Priory. The priory was built by King Alexander III of Scotland following the discovery here of a cross and relics of St Nicholas of Myrna.
A fine cross was found on the site of the Cross Kirk in 1241, followed by the discovery of a stone urn containing what some claimed were the remains of St Nicholas. The church was founded there that century to mark the discovery of these sacred items.
The 1200s western doorway is the most significant feature to survive of the church, which stands surrounded by attractive mature Scots pine.
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.