The area was part of the Roman province of Illyricum. Bosnia was settled by Serbs in the 7th cent.; it appeared as an independent country by the 12th cent. but later at times acknowledged the kings of Hungary as suzerains. Medieval Bosnia reached the height of its power in the second half of the 14th cent., when it controlled many surrounding territories. Bosnia also annexed the duchy of Hum, which, however, regained autonomy in 1448 and became known as Herzegovina. During this period the region was weakened by religious strife among Roman Catholics, Orthodox, and Bogomils. Thus disunited, Bosnia fell to the Turks in 1463. Herzegovina held out until 1482, when it too was occupied and joined administratively to Bosnia. The nobility and a large part of the peasantry accepted Islam.
Under Turkish rule, Bosnia and Herzegovina's economy declined. Physical remoteness facilitated the retention of medieval social structure, including serfdom (remnants of which lasted until the 20th cent.). Refusal by the Turkish to institute reforms led to a peasant uprising (1875) that soon came to involve outside powers and led to the Russo-Turkish War of 1877–78. After the war, the Congress of Berlin (1878) placed Bosnia and Herzegovina under Austro-Hungarian administration and occupation, while recognizing the sovereignty of the Turkish sultan. Austria-Hungary improved economic conditions in the area but sought unsuccessfully to combat rising Serb nationalism, which mounted further when Bosnia and Herzegovina were completely annexed in 1908.
The assassination (1914) of Archduke Francis Ferdinand by a Serb nationalist in Sarajevo precipitated World War I. In 1918, Bosnia and Herzegovina were annexed to Serbia. The dismemberment of Yugoslavia during World War II led to Bosnia and Herzegovina's incorporation into the German puppet state of Croatia. Much partisan guerrilla warfare raged in the mountains of Bosnia during the war. In 1946, Bosnia and Herzegovina became one of the six constituent republics of Yugoslavia. Under the Communist regime Bosnia remained relatively undeveloped. Economic problems and ethnic quarrels during the 1980s led to widespread dissatisfaction with the central government.
In Oct., 1991, following the secession of Slovenia, Croatia, and Macedonia, the Croats and Bosniaks of Bosnia and Herzegovina, fearing Serbian domination, voted for a declaration of independence from Yugoslavia. In 1992, the sovereignty of Bosnia and Herzegovina was recognized by the European Community (now the European Union) and the United States, and it entered the United Nations. Many Bosnian Serbs opposed the new republic, in which they were a minority, and Serb troops, both from Serbia and Bosnia, began to carve out the Serb-populated areas and declared the Serbian Republic of Bosnia and Herzegovina. Croats in Bosnia, also fearing Bosniak domination, declared their own Croatian Community of Herceg-Bosna.
An arms embargo reinforced the disparity between the well-armed Serbs and their foes, and Bosniaks were forced from their homes and towns as part of an "ethnic cleansing" policy carried out mostly by the Serbs. Thousands were killed, many were placed in detention camps, and many more fled the country. (Bosnian Serb leader Radovan Karadžić was among a number of Serbs later indicted in absentia by a United Nations tribunal for war crimes; he was finally arrested and extradited to The Hague by Serbia in 2008.) The major Western powers rejected military intervention but endorsed the establishment of six "safe areas" with a United Nations presence, where Bosniaks would supposedly not be attacked.
Fighting between Bosniaks and Croats intensified in 1993. Shelling, mainly by Serb forces, destroyed much of Sarajevo and laid waste to other cities throughout the country. In 1994, Yugoslavian and Croatian forces fought in support of Bosnian Serbs and Croats, respectively. The Bosnian government army launched major offensives from Bihac and elsewhere, and the balance of power among Serbs, Croats, and Bosniaks shifted from time to time.
In 1994, Bosniaks and Bosnian Croats agreed to a cease-fire and established a joint Federation of Bosnia and Herzegovina. During 1995, Serb forces shelled the besieged Sarajevo and launched attacks on the UN-proclaimed "safe areas" of Tuzla, Zepa, and Srebrenica. There were mass deportations of Bosniaks and widespread instances of rape and execution of civilians, especially in Srebrenica. Croat and Bosniak forces later made heavy inroads against Serbs in western Bosnia. An estimated 97,000 to 110,000 persons died during the years of fighting; roughly two thirds of those who died were Bosniaks.
In late 1995, the Bosniak-dominated Bosnian government and the leaders of Croatia and Serbia met under U.S. auspices in Dayton, Ohio, and negotiated a peace accord. It called for a Bosnian republic with a central government and two semiautonomous regions, roughly equal in size, one dominated by Serbs, the other by Bosniaks and Croats in federation. The accord provided for the dispatch of NATO-led troops for peacekeeping purposes; the forces originally were to stay until June, 1998. In addition, a high representative of the Peace Implementation Council (the nations overseeing the peace process) is the final authority on the civilian aspects of the settlement, and has the power to dismiss elected Bosnian officials. The accord was implemented and conditions have slowly improved.
Bosnian disillusionment with the moderates who had held power since 1998 resulted in electoral victories for the ethnic nationalist parties in the 2002. The peacekeeping forces Bosnia were transferred in 2004 from NATO's leadership to the European Union's. In 2006 the International Court of Justice began hearing Bosnia's genocide case against Serbia. The charges, which were first filed in 1993, accused Serbia of state-planned genocide against Bosnian Muslims. The court, which had limited access to internal Serbian evidence, did not find Serbia guilty of genocide (which would have required proving intent on the part of Serbia's leaders) but did find (2007) that Serbia had violated international law when it failed to prevent or prosecute those responsible for genocide against the Bosniaks.
Bosnian political leaders agreed in Mar., 2006, to constitutional revisions that would establish a single-person presidency and move the country toward a strong-prime-minister parliamentary system. The changes, designed to strengthen the central government, were also intended to promote Bosnia's accession to the European Union and NATO. The following month, however, the reforms failed to win the required two-thirds majority in the parliament.
Much distrust remains among Bosnia's three communities, whose members now typically live in areas that are largely ethnically homogeneous, and the Oct., 2006, presidential and parliamentary elections for the central government reinforced and even exacerbated ethnic divisions. In Apr., 2008, the parliament approved the unification of Bosnia's police forces, but the watered-down law largely left Serb police forces outside central control. Austrian diplomat Valentin Inzko became the international high representative in Mar., 2009. The European Court of Human Rights ruled in Dec., 2009, that Bosnia's constitution contains unlawful and discriminatory provisions and called for it to be revised, but the process of doing so proved difficult and prolonged, extending into 2012. In the Oct., 2010, elections, moderate candidates won the Muslim and Croat presidency seats, but the Serb seat was won by a nationalist. The formation of a new central government was not achieved, however, until Feb., 2012, and in June disputes over the budget threatened the government.