Belgium occupies part of the Roman province of Belgica, named after the Belgae, a people of ancient Gaul. The area was conquered by Julius Caesar in 57–50 B.C., then was overrun by the Franks in the 5th century A.D. It was part of Charlemagne's empire in the 8th century, then in the next century was absorbed into Lotharingia and later into the duchy of Lower Lorraine. In the 12th century it was partitioned into the duchies of Brabant and Luxembourg, the bishopric of Liège, and the domain of the count of Hainaut, which included Flanders. In the 15th century, most of the Low Countries (currently the Netherlands, Belgium, and Luxembourg) passed to the duchy of Burgundy and were subsequently inherited by Emperor Charles V. When the latter abdicated in 1555, they went to his son Philippe II, king of Spain. While the northern part, now the Netherlands, gained its independence in the following decades, the southern part remained under Spanish control until 1713, when it was transferred to Austria. During the wars that followed the French Revolution, Belgium was occupied and later annexed to France. But with the downfall of Napoléon, the Congress of Vienna in 1815 reunited the Low Countries under the rule of the king of Holland. In 1830, Belgium rebelled against Dutch rule and declared independence, which was approved by Europe at the London Conference of 1830–1831.

Germany's invasion of Belgium in 1914 set off World War I. The Treaty of Versailles (1919) gave the areas of Eupen, Malmédy, and Moresnet to Belgium. Leopold III succeeded Albert, king during World War I, in 1934. In World War II, Belgium was overwhelmed by Nazi Germany, and Leopold III was held prisoner. When he returned at the government’s invitation in 1950 after a narrowly favorable referendum, riots broke out in several cities. He abdicated on July 16, 1951, and his son, Baudouin, became king. Because of growing opposition to Belgian rule in its African colonies, Belgium granted independence to the Congo (now Democratic Republic of the Congo) in 1960 and to Ruanda-Urundi (now the nations of Rwanda and Burundi) in 1962.

Since 1958, when the European Economic Community was born, Brussels, the country’s capital, has gradually established itself as the de facto capital of what has now become the European Union (EU), a role that became official in Dec. 2000 when the European Council of heads of government decided to hold all its regular meetings in Brussels. As a result, the city has become home not only to nearly 20,000 European civil servants, but to an even more numerous community of lobbyists, lawyers, and other professionals drawn to the EU’s main decision center.

Growing divisions between Flemings and Walloons, and devolution along linguistic lines, culminated in the revised constitution of 1994, which turned Belgium into a federal state with significant autonomy for its three regions and its three language “communities.”

In the 1990s Belgium’s public life was shaken by a number of serious scandals. In 1991, a former deputy prime minister and socialist leader was murdered in a contract killing that took several years to be elucidated. In 1998, along with two other major Belgian politicians, former NATO secretary-general Willy Claes was convicted of bribery. The Dutroux child-sex-and-murder affair in 1996 led to national outrage, compounded by the realization that less official negligence and inefficiency could have saved the lives of several children. It fueled pressure for reform of the political, judicial, and police systems. In 1999, a public health scandal involving dioxin, a cancer-causing chemical, resulted in the unexpected electoral defeat of Christian-Democratic prime minister Jean-Luc Dehaene.

In June 1999, the new prime minister, Guy Verhofstadt of the Liberal Party, cobbled together a coalition of liberals, socialists, and greens, which was continued, without the green parties, after the May 2003 election. His government passed extremely liberal social policies, including the legalization of gay marriage and euthanasia and the partial decriminalization of marijuana. Against the wishes of the prime minister’s party, a parliamentary majority also extended voting rights at local elections to all foreign residents.

In Nov. 2004, a Belgian court ruled that the far-right party Vlaams Blok, a nationalist and anti-immigration party that accounts for over 20% of the vote in Flanders, was guilty of violating antiracism laws, and thus ineligible for funding or television access. The party has since changed its name to Vlaam Belang (“Flemish interest”) and attempted to cleanse its party program.

Prime Minister Verhofstadt resigned in June 2007, after his coalition of liberals and socialists took a drubbing in a general election. He remained in office as caretaker prime minister for more than six months, however, as talks between Flemish-speaking and French-speaking parties on forming a government reached a deadlock, leaving the country in political crisis. At King Albert II's request, Verhofstadt formed an interim coalition government in December 2007.

On March 20, 2008, Yves Leterme was sworn in as prime minister, ending the political crisis that spanned nine months. A new government was formed that includes both Flemish and French-speaking democrats, liberals, and socialists.