The Church of San Dionisio was built in the late 15th century in Gothic-Mudéjar style, although its interior was later renovated in Baroque style (18th century) by architects Diego Antonio Díaz and Pedro de Silva.
The parish was established by Alfonso X the Wise in the name of Saint Denis as the city was returned to Christian rule on Saint Denis's Day in 1264.
The church has a basilica plan, divided into three naves by tall and simple pillars adorned with Almohad decorations. The arcades (aside from those near the high altar) are ogival. The naves end with apses with Baroque altars, including the high altar which dates to the pre-Baroque renovation.
The side chapels are in Baroque style. The chapel of the Christ of the Water includes an image of Jesus from the 15th century. The tower known as Torre de la Atalaya was also built in the fifteenth century. Although this is attached to the church it was a civilian construction intended to serve as a watchtower for both fires and attack and to hold the town's clock. The tower has been separately listed from the church as being of cultural interest. The tower was first mentioned in 1447 and the clock was installed in 1454 and the tower was first used as a watchtower in 1484.
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.