From 829, Pannonia became part of Bulgaria following the collapse of the Avar Khaganate and a defeat of the forces of the Holy Roman Empire under Louis the Pious at the hands of a Bulgarian army under Omurtag.

After the Bulgarian–Hungarian Wars, Buda and Pest started to develop economically in the 12th century, largely due to the French, Walloon and German settlers who migrated there and worked and traded under royal protection along the banks of the Danube.

Both towns were devastated during the Mongol invasion of Europe in 1241–42[4] and subsequently rebuilt by colonists from Germany, who renamed Buda "Ofen" ("furnace"), after its numerous lime kilns.

They built a succession of palaces on the Várhegy (Castle Hill) and reached their zenith of power and prestige during the Renaissance under "Good King" Matthias Corvinus (Hunyadi Mátyás), who reigned from 1458 to 1490.

In the first decades of the following century, Pest became the center of the Reform movement led by Count Széchenyi, whose vision of progress was embodied in the construction of the Lánchíd (Chain Bridge).

With the leadership of Lajos Kossuth (1802–94) and the "people's rights-liberals" dominated parliament, Sándor Petőfi (1823–49), also a renowned poet, and his fellow revolutionaries began to plot downfall of the Habsburgs in Budapest at the Café Pilvax (which exists to this day in central Pest).

[5] While competing with Vienna, the country's resources were concentrated in Budapest (e.g. through tax breaks) Its favourable transport-geographical position was reinforced by the radially built road and rail network.

The Council was composed of aristocrats - Gyula Andrássy and Baron Frigyes Podmaniczky - who planned and proportioned the inner area of Budapest, creating large ring roads and boulevards.

The Heroes' Square and Vajdahunyad Castle, located at end of Andrássy Avenue are just two perfect examples of the monumental scale and style that influenced the period.

New suburbs were created to make room and house the rapidly growing and financially expanding population, which by now was predominantly Magyar, although there developed a sizable German as well as a Jewish community due to immigration to the city.

In the aftermath of World War I which had led to the collapse of the Austro-Hungarian Empire, half of the Hungarian population was cut away from Hungary by the Treaty of Trianon and made part of surrounding nations.

Yet Horthy was considered a moderate compared to the fascist Arrow Cross Party, whose power grew as World War II raged across Europe.

Despite discriminatory legislation against the Jews and widespread antisemitism, the Jewish community of Budapest was relatively secure until the German occupation of Hungary in March 1944 (Operation Margarethe).

Hundreds of Jews were rounded up and interned in the Kistarcsa transit camp (originally established by Hungarian authorities), 15 miles (24 km) northeast of Budapest.

They were aided by foreign diplomats like Nuncio Angelo Rotta, Raoul Wallenberg, Giorgio Perlasca, Carl Lutz, Friedrich Born, Harald Feller, Angel Sanz Briz and George Mandel-Mantello who organized false papers and safe houses for them.

In October 1944, Germany orchestrated a coup and installed a new Hungarian government dominated by the fascist Arrow Cross Party under Ferenc Szálasi.

On November 8, 1944, the Arrow Cross militia concentrated more than 70,000 Jews—men, women, and children—in the Ujlaki brickyards in Obuda, and from there forced them to march on foot to camps in Austria.

There, the Germans took them to various concentration camps, especially Dachau in southern Germany and Mauthausen in northern Austria, and to Vienna, where they were employed in the construction of fortifications around the city.

Between December 1944 and the end of January 1945, the Arrow Cross took Jews from the ghetto in nightly razzias, as well as deserters from the Hungarian army or political enemies, shot them along the banks of the Danube and threw their bodies into the river.

A two-month-long siege of Budapest reduced the entire city, but mostly the Castle District to rubble, as it was assigned to the mostly Hungarian army with German leadership to defend and to "hold back".

[citation needed] Arrests, beatings or summary executions were used as a standard tool by the Secret Police, who employed an extensive net of informants.

[citation needed] By this time the administration was composed predominantly of hardline communists or careerists, who made up the Soviet-accepted controllers of wealth and power.

He had gained widespread popularity by distributing land to farmers, and the support of the elite by practicing self-criticism and completing party programs, even when it conflicted with his proposals.

During this time, the CIA-sponsored Radio Free Europe broadcast effective methods of urban combat, including constructing barricades and producing explosives.

When the tanks and elite forces opened fire on the mass protest situated in front of the Parliament buildings, they caused a national uprising overnight.

[citation needed] Soviet units were ordered to invade, along with the militaries of the surrounding nationalities of the Warsaw Pact, with which Hungary already had a strained history.

[citation needed] A decade later, the city was the center of opposition activity, rallies, printing and selling of unauthorized material and secret-service surveillance.

[citation needed] Finally, the majority of the multi-sided regime decided to step over Gorbachev's line and open the borders (the first official break of the Iron Curtain), declared Hungary a Republic on October 23, 1989 then issued free elections.

[citation needed] While communism was toppled in Berlin and Prague, the Hungarian Socialist Workers' Party was simply voted out of power in Hungary, initiating a peaceful transition from one political system to another.

In October 2019, opposition candidate Gergely Karácsony won the Budapest mayoral election, meaning the first electoral blow for Hungary’s nationalist prime minister Viktor Orbán since coming to power in 2010.