Keiss Castle is a partially ruined castle which was replaced by the Keiss House around 1755. The old castle was built possibly on the site of an earlier fort in the late 16th or early 17th century by George 5th Earl of Caithness (1582-1643). It seems the castle was in existence in 1623 when James I commissioned Sir Robert Gordon to enter Caithness with an armed force. The 7th Earl died in the castle in 1698 but it is reported that the castle was ruinous in 1700 and in 1726 as being in repair with 'at the side of it a convenient house lately built'. The estate was purchased by Sir William Sinclair, 2nd Baronet of Dunbeath early in the 18th century and in 1752 Keiss became his family seat.
The current house was built about 1755 but had to be sold in 1765 because of financial difficulties to the Sinclairs of Ulbster. This Category B Listed Baronial mansion was altered to its current form on the instructions of Col. K Macleay by David Bryce in 1860, during which it was extended in the Scottish baronial style. It was then sold to the Duke of Portland in 1866. Also included in the listing is the Walled garden to the NE of the house and the gate lodge and gate piers with cast-iron carriage gates installed in the 1860 alterations.
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.