Bosnia has been inhabited at least since Neolithic times. In the early Bronze Age, the Neolithic population was replaced by more warlike Indo-European tribes known as the Illyres or 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. Conflict between the Illyrians and Romans started in 229 BCE, but Rome wouldn't complete its annexation of the region until 9 CE. In the Roman period, latin-speaking settlers from all over the Roman Empire settled among the Illyrians and Roman soldiers were encouraged to retire in the region.
The 1990 parliamentary elections led to a national assembly dominated by three ethnically-based parties, which had formed a loose coalition to oust the communists from power. Croatia and Slovenia's subsequent declarations of independence and the warfare that ensued placed Bosnia and Herzegovina and its three constituent peoples in an awkward position. A significant split soon developed on the issue of whether to stay with the Yugoslav federation (overwhelmingly favored among Serbs) or seek independence (overwhelmingly favored among Bosniaks and Croats). A declaration of sovereignty in October of 1991 was followed by a referendum for independence from Yugoslavia in February and March 1992 boycotted by the great majority of Bosnian Serbs. With a voter turnout of 64%, 98% of which voted in favor of the proposal, Bosnia and Herzegovina became an independent state. Following a tense period of escalating tensions and sporadic military incidents, open warfare began in Sarajevo on April 6.
International recognition of Bosnia and Herzegovina meant that the Yugoslav People's Army (JNA) officially withdrew from the republic's territory, although their Bosnian Serb members merely joined the Army of Republika Srpska. Armed and equipped from JNA stockpiles in Bosnia, supported by volunteers and various paramilitary forces from Serbia, and receiving extensive humanitarian, logistical and financial support from the Federal Republic of Yugoslavia, Republika Srpska's offensives in 1992 managed to place much of the country under its control. By 1993, when an armed conflict erupted between the Sarajevo government and the Croat statelet of Herzeg-Bosnia, about 70% of the country was controlled by the Serbs.
In March 1994, the signing of the Washington accords between the leaders of the republican government and Herzeg-Bosnia led to the creation of a joint Bosniak-Croat Federation of Bosnia and Herzegovina. This, along with international outrage at Serb war crimes and atrocities (most notably the genocidal killing of 8,000 Bosniak males in Srebrenica in July, 1995), eventually turned the tide of war. The signing of the Dayton Agreement in Dayton, Ohio by the presidents of Bosnia and Herzegovina (Alija Izetbegovi?), Croatia (Franjo Tu?man), and Yugoslavia (Slobodan Miloševi?) brought a halt to the fighting, roughly establishing the basic structure of the present-day state. The three years of war and bloodshed had left 102,000 people killed and more than 2 million displaced.