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:Trenčín Castle is relatively large renovated castle, towering on a steep limestone cliff directly above the city of Trenčín. It is a dominant feature not only of Trenčín, but also of the entire Považie region. The castle is a national monument.
History of the castle cliff dates back to the Roman Empire, what is proved by the inscription on the castle cliff proclaiming the victory of Roman legion against Germans in the year 179.
Today’s castle was probably built on the hill-fort. The first proven building on the hill was the Great Moravian rotunda from the 9th century and later there was a stone residential tower, which served to protect the Kingdom of Hungary and the western border. In the late 13th century the castle became a property of Palatine Matúš Csák, who became Mr. of Váh and Tatras.
Matúš Csák of Trenčín built a tower, still known as Matthew’s, which is a dominant determinant of the whole building.