The Citadel was built by personal order of Tsar Nicholas I after the 1830 November Uprising. It's chief architect, Major General Ivan Dehn, used the plan of a fortress in Antwerp as the basis for his own plan. The cornerstone was laid by Field Marshal Ivan Paskevich, de facto viceroy of Russian Poland.
The fortress is a pentagon-shaped brick structure with high outer walls, enclosing an area of 36 hectares. Its construction required the demolition of 76 residential buildings and the forcible resettlement of 15,000 inhabitants. Work on it officially commenced 4 May 1834, to mark the 18th birthday of Russian Crown Prince Alexander, for whom it was named. In reality, however, the fortress was not completed until 1874. The cost of construction came to 11 million rubles (roughly 8.5 tonnes of pure gold or 128 million euro by today's' prices), a colossal sum by 19th-century standards, and was borne entirely by the city of Warsaw and the Bank of Poland, as yet another punishment for the failed uprising.
In peacetime, some 5,000 Russian troops were stationed there. During the 1863 January Uprising, the garrison was reinforced to over 16,000. By 1863 the fortress housed 555 artillery pieces of various calibers, and could cover most of the city center with artillery fire.
About the fortress 104 prison casemates were built, providing wards for 2,940, mostly political, prisoners. The list of Poles imprisoned and/or executed there up through World War I reads like a Who's Who of notable patriots and revolutionaries. They include persons as diverse as Romuald Traugutt, leader of the 1863 January Uprising; Jaroslaw Dabrowski, later military chief of the 1871 Paris Commune; Feliks Dzierzynski, a leader of the Russian Revolution of 1917 and founder of the Cheka secret police; the Marxist theoretician and revolutionary, Rosa Luxemburg; the future Marshal of Poland, Józef Pilsudski; Pilsudski's political archrival, Roman Dmowski; and Eligiusz Niewiadomski, assassin of Poland's first president, Gabriel Narutowicz. The Citadel's infamous Tenth Pavilion has, since 1963, served as a museum.
Well before the turn of the 20th century, it was apparent that such traditional fortifications had been made obsolete by modern rifled artillery. The Tsarist authorities had planned in 1913 to raze the fortress, but the process had not begun before the outbreak of World War I. In 1915 Warsaw was occupied by German forces with little opposition from the Russian garrison, which abandoned the fortress and withdrew east. The Germans blew up several of its structures, but the main part of the Citadel remained intact.
After Poland regained her independence in 1918, the Citadel was taken over by the Polish Army. It was used as a garrison, infantry training center, and depot for war materiel. During the 1944 Warsaw Uprising, its German garrison prevented Armia Krajowa units from the city center from linking up with units from northern Warsaw's Zoliborz district. The fortress survived the German occupation and in 1945 again became Polish Army property.