Pre-Roman history The area of the county has been inhabited since
Neolithic times famous for its
Vučedol culture and
La Tène culture sites. It includes exceptionally rich archaeological sites, listed among the most important sites of southern Europe many of which are preserved today at the
Vučedol Culture Museum.
Roman Sirmium During the classical times, the Danube river was a part of the
Danubian Limes. It was a birthplace of Roman emperors
Valentinian I and
Valens while the entire region was oriented towards the nearby
Sirmium, a city declared one of four capitals of the Roman Empire in 294.
Middle Ages Ottoman period During the
Ottoman Hungary period the region was a part of the
Sanjak of Syrmia with seat in contemporary town of
Ilok.
Habsburg Empire and Austria-Hungary The Ottoman Empire retreated from the region after the signing of the 1699
Treaty of Karlowitz. The region became a part of the Habsburg
Kingdom of Slavonia and
Slavonian Military Frontier as part of the
Habsburg Monarchy (until 1804),
Austrian Empire (1804–1867) and
Austria-Hungary (1867–1918). The historical Slavonian
Syrmia County, with its seat also in Vukovar, existed for most of the period between 1745 and 1922. During the
revolutions of 1848 in the Austrian Empire the historical county and parts of the Military Frontier, including most of modern Vukovar-Srijem County, briefly became part of the short-lived self-declared
Serbian Vojvodina. In the aftermath, from 1849, the Military Frontier was restored and the historical county was split: the eastern part became part of the Neusatz (
Novi Sad) district of the
Voivodeship of Serbia and Banat of Temeschwar crown land; the western part, which broadly corresponded to the northern part of modern Vukovar-Srijem County, including Vukovar, was merged into the Essek (
Osijek) county of Slavonia. The border between the two was broadly similar, but not identical, to the modern Croatia-Serbia border; notably, Ilok lay just to the east of the border, and it ran through what is today
Bapska, dividing Bapska-proper (in Neusatz) and Novak (in Essek). In 1860 the pre-1848 divisions, including the historical Syrmia County, were restored. In 1881 the Slavonian Military Frontier was abolished and large parts of it were merged into Syrmia County. Between 1881 and 1922 it covered the contemporary county and the area of modern-day
Srem District (except
Mačvanska Mitrovica),
Zemun,
Surčin and
New Belgrade subdivisions of Belgrade, easternmost parts of
Brod-Posavina County and
Petrovaradin,
Beočin,
Neštin,
Vizić and
Sremski Karlovci.
World War I Kingdom of Yugoslavia Some of the villages in the region were settled by
Salonica front Serbian soldiers and families as a reward for their contribution to war efforts. The old Habsburg Syrmia County remained a subdivision of the
Kingdom of Serbs, Croats and Slovenes (Yugoslavia from 1929) until 1922; it then became an oblast (with the same borders) until 1929. From 1929 it was split between the
Sava and
Danube Banovinas until 1939; the modern Vukovar-Srijem County was mostly contained with Sava Banovina. In 1939 Sava Banovina was merged into the
Banovina of Croatia and its borders extended, encompassing all of the modern county.
World War II During World War II the region was part of the Nazi puppet
Independent State of Croatia, mostly within
Vuka County, with southern parts falling within
Posavje County. The puppet state and Nazi forces conducted criminal policy of
Holocaust,
Genocide of Serbs in the Independent State of Croatia and
Romani genocide by destruction of
Vinkovci Synagogue, devastation of
Vukovar Synagogue,
Dudik Killings,
Ivanci massacre and other crimes in the region.
Yugoslav Partisans, Europe's most effective anti-
Axis resistance movement, was active at the
Fruška Gora mountain and in villages alongside
Zagreb–Belgrade railway (today
M105 railway). The region was liberated after the
Syrmian Front was broken.
Socialist Federal Republic of Yugoslavia In the period of the
Socialist Republic of Croatia Vukovar became an important industrial center. For a long period during the existence of the Socialist Republic of Croatia the area of the modern day county was organized in three municipalities of Vinkovci, Vukovar and Županja. At the time Croatian municipalities were on average significantly larger units (both in territory and population) than contemporary
municipalities of Croatia.
Croatian War of Independence The
Battle of Vukovar was an 87-day siege of Vukovar by the
Yugoslav People's Army (JNA), supported by various paramilitary forces from Serbia, between August and November 1991. Before the Croatian War of Independence the Baroque town was a prosperous, mixed community of Croats, Serbs and other ethnic groups. As Yugoslavia began to break up, Serbia's President
Slobodan Milošević and Croatia's President
Franjo Tuđman began pursuing nationalist politics. In 1990, an
armed insurrection was started by Croatian Serb militias, supported by the Serbian government and paramilitary groups, who seized control of Serb-populated areas of Croatia.
Battle of Borovo Selo was one of the first armed clashes which led to the War. Despite the battle the events in Eastern Slavonia developed slower than in Krajina and were under much stronger and more direct influence from the central government in
Belgrade. They however led to the establishment of self-proclaimed
SAO Eastern Slavonia, Baranja and Western Syrmia which subsequently joined the as well self-declared
Republic of Serbian Krajina. The region was ethnically cleansed of its Croat and some other non-Serb population leading to some of the most serious violation of human rights including
Erdut killings,
Lovas killings,
Dalj massacre,
Tovarnik massacre,
Vukovar massacre and
other crimes. Within the Republic of Serbian Krajina there was no direct physical connection between the Krajina and Eastern Slavonia, and no later than 1994 there was effective detachment and schism between
Pale-aligned and more hardline
Knin administration and more compromising and Belgrade aligned Vukovar administration. Complete military defeat of Krajina during the
Operation Storm and perception that similar or more devastating fate may follow up in Eastern Slavonia increased willingness to compromise and commitment on all sides to pursue peaceful resolution of the conflict. As the result of the War Vukovar became known in majority Croat community as the
Hero City and is today a common emotional patriotic or nationalist reference commemorated officially as a Remembrance Day
public holiday on November 18.
United Nations administration On 12 November 1995
Erdut Agreement between the authorities of the
Republic of Croatia and the local Serb authorities of the
Eastern Slavonia, Baranja and Western Syrmia was reached enabling peaceful resolution to the Croatian War of Independence in eastern Croatia. The agreement was acknowledged by the
United Nations Security Council in its
Resolution 1023 and subsequent resolutions dealing with the newly established
United Nations Transitional Administration for Eastern Slavonia, Baranja and Western Sirmium. The mission successfully demilitarized the region and returned it to government's control over the two year period. It enabled the return of Croat refugees and provided inter-communal power-sharing mechanisms in police and other institutions as well as the establishment of minority institutions such as the
Serb National Council and regional
Joint Council of Municipalities.
Contemporary period In the aftermath of the direct United Nations Administration
OSCE Mission to Croatia was present in the region. ==Geography==