In Slavonski Brod, one of the important strategic and traffic places that controlled the most important crossing on the Sava to Bosnia and connected the main trade routes, between 1715 and 1780 the great Imperial and Royal Slavonian border fortress Brod was built. With its extensions, this baroque complex of fortifications is the largest building of its kind in Croatia, and among the largest in Europe.
In the center of the fortress square stands the baroque fortress church of St. Ana, which was closed on the south side by two buildings – the Slavonian barracks, which was renovated and today is the seat of the Classical Gymnasium of Fra Marijan Lanosović. In the restored part of the southwestern part of the Cavalier, on a gross area of 1,800 square meters. Today, the unique Ružić Gallery with the first permanent exhibition of contemporary Croatian art of the second half of the 20th century is located.