Classical Antiquity Belgrade Fortress is the core and the oldest section of the urban area of Belgrade. For centuries, the city population was concentrated only within the walls of the fortress, and thus the history of the fortress, until most recent times, reflects the history of Belgrade itself (see:
Timeline of Belgrade history). The first mention of the city is when it was founded in the 3rd century BC as "
Singidunum" by the
Celtic tribe of
Scordisci, who had defeated Thracian and Dacian tribes that previously lived in and around the fort. The city-fortress was later conquered by the Romans, was known as
Singidunum and became a part of "the military frontier", where the
Roman Empire bordered "barbarian Central Europe". Singidunum was defended by the Roman legion IV Flaviae, which built a fortified camp on a hill at the confluence of the Danube and the Sava rivers. In the period between 378 AD and 441 the Roman camp was repeatedly destroyed in the invasions by the
Goths and the
Huns. Legend says that
Attila's grave lies at the confluence of the Sava and the Danube (under the fortress). In 476 Belgrade again became the border between the empires: the
Western Roman Empire and Eastern Roman Empire (
Byzantine Empire), and the
Slav-
Avar State in the north. The Celtic fortification was a primitive one, located on top of
Terazije ridge, above the confluence of the Sava into the Danube, where the fortress still stands today. Celts also lived in small, open and fortified settlements around the fort, called
oppida. Since it is not known for sure where the Celtic fort was; some historians suggest that it was rather close to the necropolises in Karaburma and Rospi Ćuprija. Celtic settlements belonged to the
La Tène culture. The original military camp was probably occupied by the soldiers from the
Legio VIII Augusta from 46 AD to 69. Early Singidunum reached its height with the arrival of
Legio IV Flavia Felix which was transferred to the city in 86 AD and remained there until the mid 5th century. The presence of Legio IV prompted the construction of a square-shaped
castrum (fort), which occupied Upper Town of today's fortress. Construction began at the turn of the 2nd century AD as since the early 100s, Legio IV
Flavia Felix became permanently stationed in Singidunum. At first, the fortress was set up as earthen bulwarks and wooden palisades, but soon after, it was fortified with stone as the first stone fort in Belgrade's history. The remains can be seen today near the northeastern corner of the acropolis. The legion also constructed a pontoon bridge over the Sava, connecting Singidunum with Taurunum. Rectangular castrum covered what is today the Upper Town and the
Kalemegdan Park. The castrum had tall walls, built from the white
Tašmajdan limestone and spread over the area of to , being shaped as an irregular rectangle (approximately ). Belgrade remained in Serbian hands for almost a century. After the Despot's death in 1427, it had to be returned to Hungary. An attempt by the Ottoman Sultan
Mehmed II in 1456 to conquer the fortress was prevented by
Janos Hunyadi (
Siege of Belgrade), saving Hungary from Ottoman dominion for 70 years.
Early Modern In 1521, 132 years after the Battle of Kosovo, the fortress, like most parts of the Serbian state, was conquered by the
Turks and remained (with short periods of the Austrian and Serbian occupation), under the rule of the Ottoman Empire until the year 1867, when the Turks withdrew from Belgrade and Serbia. During the short period of Austrian rule (1718–1738), the fortress was largely rebuilt and modernized. It witnessed the Great Serbian Migration in the 17th century and two
Serbian Uprisings in the 19th century, during the
Turkish Period. During the
Austrian occupation of northern Serbia 1717–39, several hospitals were established in Belgrade. The City hospital of Saint John was built within the fortress walls, but its exact location is not known. Emperor
Charles VI signed the Belgrade City Statute in 1724 ("Proclamation on organizing German Belgrade"), which mentions city hospital, city pharmacy, medics and midwives. The German municipality had low incomes so it had to ask the state for help and beneficence. The hospital is mentioned in the 1728 Census. It was a hospital already in 1719, later becoming the residence of Thomas Berger, the head of the hospital. After his death, his daughter continued to reside in the building. The hospital (
Stattspital) was moved to another location, into the newly constructed building in 1724. A small church was built next to it. This new hospital was quite small, with only 2 rooms, a kitchen and a basement, so it way not be the same city hospital. Lazaret or a quarantine hospital is not mentioned in the documents, but it is safe to presume that it had to be formed during the viral outbreaks, as was usual in the time. The procedure in case of outbreaks was probably analog to the existing procedure in
Buda, the capital of
Hungary. Today unidentified disease ravaged Belgrade in 1730. Viral epidemic killed a lot of people. During the course of only two weeks, just the
Jesuits buried 220 people and themselves lost 3 missionaries. The extremely massive plague outbreak hit the city in October 1738. As the Austrian army retreated in front of the advancing Turks, numerous civilians fled to the fortress, many of them being contagious. Having so many people in a cramped space, triage was not possible so the plague spread quickly. There are reports of the dead lying in the streets for days as there was no one to bury them. The Austrian garrison was decimated and the corpses of the soldiers who died of plague were burned with their personal properties. Four outer city gates, with the adjoining walls and ramparts were demolished from 1862 (Sava, Vidin and Varoš gates) to 1866 (
Stambol Gate). After the Ottomans fully evacuated the inner fortress in 1867, Serbian troops took over, but as the state was still only autonomous (full independence was achieved in 1878), Serbia was only to "manage it" and was not acknowledged as the proprietor of the fortress by the neighboring
Austria-Hungary. First squad of Serbian soldiers, under the command of colonel Svetozar Garašanin, ceremonially replaced the Ottoman guardsmen on 18 April 1867. First action by the Serbian authorities, just 5 days after the Ottomans left in April 1867, was to rebuild the
Ružica Church. After the Ottoman withdrawal, newspapers in Austro-Hungary continuously published stories, backed by the military experts, that the fortress became strategically obsolete and that, having no value of any kind, Austrian army could destroy it in 24 hours. In the autumn of 1867 citizens were awaken by the heavy artillery fire. Ruling prince
Mihailo Obrenović sent two
batteries to the fortress (where modern
Monument of Gratitude to France is) and ordered them to fire at the fortress wall where the old wooden bridge was located. A barrage fire of 300
salvos from
De Bange cannons shelled the fortress during the entire day. It remained unclear why the prince ordered this: he decided to demolish the fortress completely, as such stories spread among the citizens; he wanted to show to the Austrians that the fortress has its values and importance, and that it can't be destroyed in a day (despite all the shelling, only of rampart was destroyed); or he simply did it to spite the Austrians. The shelling also disturbed the citizens of
Zemun, across the Sava, which was part of Austro-Hungary at the time, and some of the grenades which missed the target hit Austro-Hungarian soil, so the imperial government sent an official diplomatic note to Serbia, protesting the shelling and reminding the prince he is only a "caretaker" of the fortress. Later, while it was inhabited, the fortress formed one of the quarters in the administrative division of Belgrade. It was called
Grad ("city") for administrative purposes and continued to be translated in the foreign languages as "fortress". According to the censuses, it had a population of 2,219 in 1890, 2,281 in 1895, 2,777 in 1900, 2,396 in 1905 and 454 in 1910. Kalemegdan was the location of the second airport in Serbia, after one in the neighborhood of
Banjica from 1910. A field in the Donji Grad was adapted for planes in January 1911. It was situated along the bank of the Sava river, from the old Turkish bath (modern Planetarium) to the mouth of the Sava into the Danube. One of the flight pioneers,
Edvard Rusjan, died in an airplane crash after taking off from this field and being hit by the gust of
košava on 9 January 1911. Remains of Rusjan's plane were originally exhibited in Donji Grad and his funeral was one of the largest recorded in Belgrade. Surviving
rib of this airplane became the first exhibit in the predecessor of the modern
Aeronautical Museum Belgrade. Today, the area is used by the parachutists and paragliders and as the location of the air shows for sports and ultra-light aviation. In June 2021 it was announced that the memorial bench dedicated to Rusjan will be placed below the fortress and that surrounding green area will be named the Edvard Rusjan Park. The fortress and the park were damaged during
World War I. Serbian army had no proper weaponry to fight the Austro-Hungarian
gunboats, so they freely fired at the city from the Sava. The city was especially damaged during the heavy bombardment in 1914–1915. Diplomat and author described it in 1914: "Kalemegdan is "trimmed", the trees in the park are battered, the ancient ramparts of Singidunum crushed, all being hit by the heavy, modern artillery, from precisely measured distance and even more precisely unmeasured hatred". Heavy fighting occurred in the Lower Town in 1915, when Serbian forces, led by major
Dragutin Gavrilović, persistently but ultimately unsuccessfully, fought the invading Austro-Hungarian army. Before full occupation, Austro-Hungarian army temporarily entered Belgrade, from 3 to 14 December 1914. Already on 4 December they erected gallows in fortress' Upper Town, and on several other locations around the town, for hanging civilians. In 1928, building company "Šumadija" proposed the construction of the
cable car, which they called "air tram". The project was planned to connect Zemun to Belgrade Fortress, via Great War Island. The interval of the cabins was set at 2 minutes and the entire route was supposed to last 5 minutes. The project was never realized, but the idea of the cable car was revived in the 21st century.
Funiculars were also planned, to connect the Upper and the Lower Town. The entire Lower town was planned for demolition, with the plans including large
amusement park, museums, artificial lake, zoo, and stadiums instead of the existing military barracks. Instead of everything, the railway was conducted around the foothills of the fortress, encircling it completely, and effectively cutting it off from the Sava river, which wasn't universally accepted among the architects and urbanists of the day. During his visit to the
1936 Berlin Olympics, Yugoslav prime minister
Milan Stojadinović was fascinated by the objects built for the games, especially by the grandiose
Olympic Stadium. He instigated the
Yugoslav Olympic Committee to nominate Belgrade as the host of the 1948 Olympics and invited
Werner March, architect of the Berlin stadium, to visit Belgrade and design objects for the games. March came to Belgrade in May 1938 and suggested the Fortress' Lower Town as the location for the Olympic complex. Without architectural design competition or bidding, Stojadinović's government accepted his idea and gave him
carte blanche regarding the design. The project was finished in 1939 and the
architectural model was exhibited in October 1940 at the "Exhibition of the new German architecture" in the German pavilion at the
Belgrade Fair. In the early 1940, March began the preparatory works, as he also planned the partial remodeling of the fortress outside of the sports complex, too. He incited archaeological survey and invited German
architectural historian Daniel Krencker to study the excavations. Within the scopes of the Nazi expansion of the megaprojects, and augmentation of the German historic role and importance in this region, Krencker praised March's project as the "artistic dream, which represents rare and major German cultural act which will contribute to the old German glory of Belgrade". Just few days after German scientists left the fortress,
Germany attacked Yugoslavia on
6 April 1941. The Olympic complex was pushed aside, shifting the focus of the Germans to the archaeological exploration of the fortress during the war. After almost two millennia of continuous sieges, battles and conquests, the fortress is today known as the Belgrade Fortress. The present name of Kalemegdan Park derives from two
Turkish words,
kale (fortress) and
meydan (field), literally meaning "fortress field". After World War II, before skiing facilities were built on the mountains further from Belgrade, the slopes of Kalemegdan (so as of
Banovo Brdo,
Košutnjak and
Avala), were used by Belgraders for skiing. Also, immediately after the war, some parts of the fortress were closed for public. In some parts the new,
Yugoslav People's Army was stationed, while others were closed because of the ammunition left behind. In 2018 it was announced that the entire riverbanks section from the
Branko's Bridge on the Sava, to the
Pančevo Bridge on the Danube, will be transformed into the
linear park, patterned after the
High Line park in
New York City and
Zaryadye Park in
Moscow. It would encircle the Belgrade Fortress. In April 2019 it was announced that the park will stretch for , covering an area of . In August 2021, city expanded the project to , but only will actually make the green corridor, while the rest will be privately owned residential buildings, commercial venues and sports fields. This caused negative comments from experts. New design would actually push people away from the river, to walk along the present boulevard which encircles the fortress. The fortress itself will end up being additionally degraded and devalued, so architects and archaeologists suggested surveys, explorations and conservation of the fortress' foothills instead. The park project was described as a smokescreen, with the actual purpose of selling the riverbanks to the private investors and elevating the real estate prices. In 2022, new city administration headed by mayor
Aleksandar Šapić included in the city's urban plan relocation of the Belgrade Zoo out of the fortress. In February 2023, Šapić announced relocation to the
Ada Safari section of
Ada Ciganlija island. City manager, Miroslav Čučković, explained the relocation: "Since the foundation of the new city administration...we made decisions which are connected to our dedication to spaces to which Belgraders were coming close to in all of these previous years. Those are spaces for which we think should have some new type of content and possibility to directly invest into them". Šapić added that the "political decision was made to handle this", and, if everything goes by the plan, the relocation might be finished in three years. Public and experts' backlash against the project was massive, mostly regarding hastiness, arbitration, irrelevance, legality and selected location. Public speculated that the residents of the newly built affluent K-Distrikt residential complex across the zoo are bothered by the smell, or that some more lucrative structures might be built instead of the zoo on such exceptional location, since "direct investments" were given as one of the reasons. Šapić then retreated a bit, stating this is just a "political idea" which is not hastily made, that only now analyses and surveys will be done to check the viability, that nothing will be built instead of the zoo but the fortress will be
conserved instead, and that there is no set time frame for the project. == Archaeology ==