The Church of St. Denis in Liège is a former fortified collegiate church, founded by Notker of Liège in 987 and first consecrated on 12 March 990. The tower was added around 1100. The church has since 1936 been registered as a listed building, and is currently listed as 'exceptional heritage' of Wallonia. The collegiate church was suppressed in 1797, but the building was taken into use as a parish church in 1803.
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.