During the history, name Slavonian Military Frontier referred to different territories. It was first located in what is now Central Croatia and was known as the Varaždin generalat. It was created from territories that had been part of medieval Banovina of Slavonia. Shortly after its creation in the 16th century, original Slavonian Military Frontier bordered the Ottoman Empire to the east, the Habsburg Kingdom of Croatia to the west, the Croatian Military Frontier to the south-west, and the Habsburg Kingdom of Hungary, also part of the Habsburg Empire, to the north. After the Treaty of Karlowitz, Habsburg Monarchy expanded its territory towards east and new sections of the Military Frontier were founded along the Sava, Danube, Tisa and Mureş rivers. New parts of the frontier were divided into two generalats: the first one included territory from Gradiška to river Tisa and the second one included territories along the Tisa and Mureş rivers. Until the middle of the 18th century, the entire Slavonia region was under military administration. In 1745, northern parts of Slavonia were placed under civil administration and were organized into the newly formed Habsburg crownland known as the Kingdom of Slavonia. The southern parts of Slavonia that remained under military administration were organized into Slavonian Military Frontier, while former original Slavonian Military Frontier was organized as Varaždin section of the Croatian Military Frontier. In the second half of the 18th century, the Slavonian Military Frontier bordered the Habsburg Kingdom of Croatia and the Croatian Military Frontier to the west, the Habsburg Kingdom of Slavonia and the Habsburg Kingdom of Hungary to the north, the Banat Military Frontier to the east and the Ottoman province of Bosnia and Sanjak of Smederevo to the south. In 1783 it was placed under the unified control of the Croatian General Command headquartered in Zagreb. The only changes of this province's borders and neighborhood before its integration into Kingdom of Croatia-Slavonia in 1881 were in 1848–1849 when autonomous Serbian Vojvodina included eastern parts of Slavonian Military Frontier and between 1849 and 1860, during the existence of Voivodeship of Serbia and Banat of Temeschwar, a separate Habsburg crownland which became a north-eastern neighbor of Slavonian Military Frontier. After the creation of the Principality of Serbia in 1815, this was their southeastern neighbor.
Population and demographics
1776
In 1776, the rural population of the Slavonian military frontier was 177,212. The number of Roman Catholic men was 43,635, while number of Orthodox men was 33,970. The number of inhabitants of cities was 11,353, and that giving a total of 188,565 inhabitants. In Brod and Gradiška regiments Catholics outnumbered the minority Orthodox, and in Petrovaradin regiment the Orthodox were more numerous.
1820
In 1820, population of Slavonian Military Frontier included 117,933 Catholics and 117,274 Orthodox Christians.
1870
In 1870, Slavonian military frontier had, according to official census, 246,901 inhabitants. Of that number 143,873 were Roman Catholic and 92,991 were Orthodox. Brod regiment had 82,540 inhabitants out of which 73,892 were Roman Catholic and 6,886 were Orthodox. Gradiška regiment had 61,596 inhabitants out of which 45,601 were Roman Catholic and 15,933 were Orthodox. Petrovaradin regiment had 102,765 inhabitants out of which 70,172 were Orthodox and 24,380 were Roman Catholic.
