Bosnia and Herzegovina, sometimes referred to simply as Bosnia, is a country in Southeastern Europe on the Balkan Peninsula. It has had permanent settlement since the Neolithic Age. By the early historical period it was inhabited by Illyrians and Celts. Christianity arrived in the 1st century, and by the 4th century the area became part of the Western Roman Empire. Germanic tribes invaded soon after, followed by Slavs in the 6th Century. In 1136, Béla II of Hungary invaded Bosnia and created the title "Ban of Bosnia" as an honorary title for his son Ladislaus II of Hungary. During this time, Bosnia became virtually autonomous, and was eventually proclaimed a kingdom in 1377. The Ottoman Empire followed in 1463 and lasted over 400 years. They wrought great changes to the political and administrative system, introduced land reforms, and class and religious distinctions. A series of uprisings began 1831, which culminated in the Herzegovinian rebellion, a widespread peasant uprising, in 1875. The conflict eventually forced the Ottomans to cede administration of the country to Austria-Hungary through the Treaty of Berlin in 1878. The establishment of the Kingdom of Yugoslavia in 1929 brought the redrawing of administrative regions into the Kingdom of Yugoslavia which purposely avoided all historical and ethnic lines, and removed any trace of Bosnian identity. The kingdom of Yugoslavia was conquered by Nazi forces in World War II, and Bosnia was ceded to the Independent State of Croatia (NDH), which led to widespread persecution and genocide. Three years of war began in 1992 which caused around 100,000 deaths and 2 million refugees.
Bosnia has been inhabited at least since Neolithic times. In the late Bronze Age, the Neolithic population was replaced by more warlike Indo-European tribes known as the Illyrians. Celtic migrations in the 4th and 3rd century BCE displaced many Illyrian tribes from their former lands, but some Celtic and Illyrian tribes mixed. Concrete historical evidence for this period is scarce, but overall it appears that the region was populated by a number of different peoples speaking distinct languages.