19th century history was closely tied to the major events in Europe. The Peace of Pressburg between Austria and France was signed in Bratislava in 1805. Theben Castle was ruined by Napoleon's French troops in 1809, and Bratislava Castle destroyed by fire in 1811. In 1843 Hungarian was proclaimed the official language in legislation, public administration and education by the Diet in Bratislava. As a reaction to the Revolutions of 1848, Ferdinand V signed the so-called March laws (also called April laws), which included the abolition of serfdom, at the Primate's Palace. The city chose the revolutionary Hungarian side, but was captured by the Austrians in December 1848. Industry grew rapidly in the 19th century. The first horse-drawn railway in the Kingdom of Hungary, from Bratislava to Svätý Jur (Szentgyörgy), was built in 1840. A new line to Vienna using steam locomotives was opened in 1848, and a line to Pest in 1850. Many new industrial, financial and other institutions were founded; for example, the first bank established in present-day Slovakia was founded in 1842. The city's first permanent bridge over the Danube, Starý most, was built in 1891.
After World War I and the formation of Czechoslovakia on October 28, 1918, the city was incorporated into the new state despite its representatives' reluctance. The dominant Hungarian and German population tried to prevent annexation of the city to Czechoslovakia and declared it a free city. However, the Czechoslovak Legions occupied the city on 1 January 1919, thereby making it part of Czechoslovakia. The city became the seat of Slovakia's political organs and organizations and became Slovakia's capital on 4-5th February. On March 27, 1919, the name Bratislava was officially adopted for the first time.. As a result of Czechoslovak independence, many Hungarian government employees migrated to Hungary, and Czechs and Slovaks took their places and moved to Bratislava. Education in Hungarian and German was radically reduced. In the 1930 Czechoslovakian census the Hungarian population of Bratislava had decreased to 15.8% (see the Demographics of Bratislava article for more details).
In 1938, Nazi Germany annexed neighbouring Austria in the Anschluss; later that year it also annexed the still-independent Petržalka and Devín boroughs on ethnic grounds. Bratislava was declared the capital of the first independent Slovak Republic on 14 March 1939, but the new state quickly fell under Nazi influence. In 1941–1942 and 1944–1945, the new Slovak government expelled most of Bratislava's approximately 15,000 Jews, with most of them being sent into concentration camps. Bratislava was bombarded by the Allies, occupied by German troops in 1944 and eventually taken by the Soviet Red Army on April 4, 1945.At the end of World War II, most Bratislava Germans were evacuated by German authorities; a few returned after the war, but were expelled without their properties under the Beneš decrees.
After the Communist Party seized power in Czechoslovakia in February 1948, the city became part of the Eastern Bloc. The city annexed new land, and the population rose significantly, becoming 90% Slovak. Large residential areas consisting of high-rise prefabricated panel buildings, such as those in the Petržalka borough, were built. The Communist government also built several new grandiose buildings, such as the Nový Most bridge and the Slovak Radio headquarters, sometimes at the expense of the historical cityscape.
In 1968, after the unsuccessful Czechoslovak attempt to liberalize the Communist regime, the city had to suffer Warsaw Pact troops occupation. Shortly after, the city became capital of the Slovak Socialist Republic, one of the two states of the federalized Czechoslovakia. Bratislava's dissidents anticipated the fall of the Communism with the Bratislava candle demonstration in 1988, and the city became one of the foremost centres of the anti-Communist Velvet Revolution in 1989.
In 1993, the city became the capital of the newly formed Slovak Republic following the Velvet Divorce. In the 1990s and the early 21st century, the city's economy boomed due to foreign investment. The flourishing city also hosted several important cultural and political events, including the Slovakia Summit 2005 between George W. Bush and Vladimir Putin.