The capital city formed in 1873 from Buda, Óbuda, and Pest was Budapest.
Budapest was officially created on November 17, 1873, when the three neighboring settlements of Buda, Óbuda, and Pest merged. The Danube divides the city: Buda and Óbuda are on the western, hillier bank, while Pest occupies the flatter eastern side. Together, they became the capital and principal urban center of Hungary.
Buda had been an important royal and political center, while Pest developed rapidly as a commercial and reform-minded city. The permanent Chain Bridge, opened in 1849, strengthened connections across the Danube and helped make a unified metropolis practical. The 1867 Austro-Hungarian Compromise also created a favorable political and economic climate for the merger.
The three names still survive in Budapest’s geography and culture, so the city is not simply an old name for one original settlement. Óbuda literally means “Old Buda,” and its Roman-era history includes Aquincum. Belgrade, Bratislava, and Bucharest are nearby regional capitals, but none was created by this 1873 merger.