In 1819 a park pavilion in the form of a knight tower was built in the Alexander Park. Nikolai Alexandrovich, the future Emperor Nicholas I, while still a Grand Duke, began to collect a collection of European and Eastern knight weapons. The Arsenal Pavilion was built by architect Adam Menelaws to store this collection.

Both the exterior and interior were built in the English medieval style, which was most suitable for storing weapons. In the rooms of the first floor there are interesting exhibitions of knight armor (including the original armor of the 16th century), as well as thematic paintings.

The center of the exposition is the large Hall of Knights on the second floor. It is there that the most valuable exhibits of the collection of Nicholas I are stored. The camping tent, “the dwelling of a medieval knight”, is installed in the center of the Hall of Knights.

Previously, you could also see there such relics as the walking-stick of the empress Catherine II, the saber of Thaddeus Kosciuszko, the ax of Shamil, the saber of Mazepa, personal belongings of the emperor Napoleon. Under Nicholas I the Arsenal was a museum of weapons, which was open for visitors, but later all its exhibits was given to the Hermitage by the emperor Alexander III.

During World War II the Arsenal was partially destroyed. It was in this state for several decades, and only in 2016 was it completely restored. The collections of knight weapons were returned there from the storerooms of the museums of St. Petersburg, and now the Arsenal is again open for visiting.