The exposition is based on a significant book collection, the beginnings of which are connected with the activities of the Brotherhood of Princes Ostrozhsky aimed to restore the castle of Princes Ostrozhsky and to create a historical museum and library in it. In 1910, the Brotherhood opened an ancient repository in Ostroh which received the first books including the Ostroh Bible of 1581 and 9 other manuscripts and printed anciently books. As of today, the collection includes 4,900 books which are exhibits of the main museum stock, including almost 1500 ancient books of the 16th -18th centuries and about 150 manuscripts of the 16th -19th centuries.
The museum is housed in Lutsk Gate Tower, a monument of defensive architecture of national importance (mid 16th century). The tower was built to protect the town on approaches from the Lutsk direction and played the role of a central link in the town’s defense system and is a barbican (rare example of a defensive structure).
