[1] Ostrogski castle was rebuilt in stone in the early 16th century under the Lithuanian rule when the city was part of the Grand Duchy of Lithuania.

He made use of the trace itallienne, or "Italian style" of fortification, to transform Dubno into the most advanced fort in the region.

During the Khmelnytsky Uprising, the vicinity of Dubno Castle was the scene of heavy fighting between the Poles and the Cossacks, some of it described by Nikolai Gogol in the novella Taras Bulba (1835).

The castle passed to Polish Prince Władysław Dominik Zasławski as part of the Ostroh inheritance and survived a Russian siege in 1660.

Some of the fortifications gave way to a plain rectangular palace of two stories, commissioned in the 1780s by Prince Stanisław Lubomirski from architects Henryk Ittar and Domenico Merlini.