Fort fortresses are a logical continuation and direct successor of bastion military fortification systems. Although created by Prussian engineers, the strong influence of the Habsburg Empire upon the German Alliance during the 19th century prompted sharing the technique with Austria as well. There, Austrian military technicians modified the system with polygonal dimension and created their own fortification school.
The system is based on a concept to surround the core of a fortress with a circle of independent forward placed forts, which in case of siege, prevent the battlefield line from penetrating the core of the fortress thus expanding the protected area.
In the Czech Republic this fortification system is only applied in the bastion fortresses of Olomouc and Terezin. The first polygonal forts in Olomouc, fort Tabulovy vrch and Šibenièní vrch were built during 1834 and 1846. Their chief designer is regarded as Ferdinand count Belrupt. The Imperial fortress Olomouc at the time was still one of the strongest in the Empire, even though lack of funding prevented finishing all of the forward placed forts.
Olomouc served for a short time as shelter for the imperial family during the 1848 revolution and again in 1850 during the culmination of tensions between Prussian and Habsburg empires. During this year, the entire XIV Army corps resided at the fortress. Also, during 28-30. November the first Austro-Prussian summit was hosted there under the patronage of the Russian tsar.
Upon resolution of the problematic events of mid-19th century, the modernization of the fortress resumed. The project was assigned to the director of Olomouc military engineer corps, Julius von Wurmb, who created a project consisting of 25 independent reduit forts surrounding the core of fortress Olomouc. This established a perimeter of approximately 17 kilometres, with the distance individual forts being 1 or 2 kilometres from each other. The furthest point from Olomouc on the perimeter being the village Křelov at 4,5 kilometers.
Thus, these forts were able to conduct independent circled defence and mutually support each other in case of enemy attack. Each fort was marked with Roman numbers from I to XXII. (Project did not include forts Tabulovy vrch and Šibeniční vrch)
The original plan however, was not realized due to lack of finances. The first four identical forts XI, XIII, XV a XVII were created between 1850 and 1854, with their design resembling the older forts of Tabulovy and Šibenièní vrch. Their construction brought an end to the era of reduit forts. During the next 25 years, the fortification system was dominated by the new artillery fortress design.
During 1851 the building site was personally visited by the emperor Franz Josef I and the Russian tsar Nicolas I. In 1853 along the Prussian prince visited as well.
From 1854 to 1857 the fortress system was further enhanced with smaller forts of a round design. These fortifications also were marked with Roman numbers II, XX, XXII. Very similar was also fort V. built during 1857 and 1863. Though contrary, two reduit forts IV and V constructed in 1856- 1862 were very different.
Important defensive role was also played by so called railroad forts I and VII, built from 1862-1865 and were half the normal size.
The remaining 8 forts III, IIIa, VI, VIII, IX, X and finally n. XVIII a XIX in Krelov area were constructed during the armouring of Olomouc fortress in 1866. Changing the original plan, construction of the remaining forts IVa, XII, XIV, XVI a XXI, was eliminated, since they were found not essential,
The war between Austria and Prussia, starting in July 1866 brought increased activity to Olomouc. History indicates forts n. X, XV and XVII did use artillery to bombard the 2nd Prussian army, but the defensive capability of the fortress was not tested since advancing Prussian forces totally avoided Olomouc, as well as Josefov and Hradec Králové. After the war was lost, the completion and modernization of Olomouc fortress was fully planned. However the construction of fort Radíkov was the last fortification activity on the Czech territory at the eve of Habsburg empire.
The strategic importance of the fortress came to an end with the edict of Franz Josef. I in March 1886. The army used all permanent forts for storage purposes, and temporary forts were left to disuse. During the First World War many forts were used as internment areas prisoners of war.
With the creation of Czechoslovakia the ownership of forts came under the Ministry of national defence, which used them for storage as well. Not even the annexing of Czechoslovakia by Nazi Germany changed their purpose.
In 1945, at the end of Second World War, the Germans established a presence at Olomouc fortress and party fortified present forts with reinforced concrete gunfire posts and bunkers. Evidenced by many holes in the walls, it is obvious some of the forts took part in confrontations with advancing Red army.
Today, many fortification elements and forts do not exist, therefore forts II, IV, VIII, XI, XIII, XV, XVII a XX were declared protected cultural monuments. Some remained in the possession of the Czech army, others found private owners.