Since the formation of Saint Petersburg in 1703, the waterways in the Gulf of Finland were of strategic importancemfor Russia. Peter I initiated the construction of forts in the Gulf of Finland and directed the foundation of the first military installation on the island of Kotlin, Fort Kronshlot, in 1704. Throughout the following two centuries, Russia continued to fortify the area.
The construction began in 1838 and under the supervision of Russian military engineer, Mikhail von der Veide. Emperor Nikolay I officially commissioned the fort on 27 July 1845. The fort was named to honor his brother, Emperor Alexander I.
The building measures 90 meters by 60 meters, with three floors. The overall floor space is over 5000 sq. meters. In all, the fort was large enough to hold a garrison of up to 1000 men. There are 100 cannon ports with additional space on the roof for 30 – 35 guns.