Alcalatén Castle, located on San Salvador Mountain in the municipality of Alcora, is an Islamic fortress with medieval architectural reforms, built between the 10th and 13th centuries.
In 1233, after the conquest of Borriana, King James I granted the castle and the title of baron to the Aragonese knight Ximén d'Urrea.
The castle, with a triangular layout, covers an area of 150 square meters. It includes a main enclosure surrounded by a patrol path, with a cistern, as well as both abandoned and inhabited areas.
At the highest point, two walls forming a right angle and topped with battlements are preserved, extending into two towers; one circular to the north and one semicircular to the south. A third tower is known to have existed, though only rubble remains from its demolition in the 15th century. The eastern section is completely destroyed. At the base of the citadel, a rectangular cistern made of mortar and stones remains, measuring approximately 4 by 10 meters. The structure is built with masonry.
The entrance is on the south side, featuring two circular towers, battlements, and a barbican-style wall.
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.