The pearl alongside the Danube

Budapest's recorded history begins with the Roman town of Aquincum, founded around 89 AD on the site of an earlier Celtic settlement near what was to become Óbuda, and from 106 until the end of the 4th century the capital of the province of lower Pannonia.

The area was occupied around the year 900 by the Magyars of Central Asia, the cultural and linguistic ancestors of today's ethnic Hungarians, who a century later officially
founded the Kingdom of Hungary.

It was Pest, a bustling commercial town, which enjoyed the faster growth rate in the 18th and 19th century and contributed the overwhelming majority of the cities' combined growth in the 19th. By 1800 its population was larger than that of Buda and Óbuda combined. The population of Pest grew twentyfold in the following century to 600,000, while that of Buda and Óbuda quintupled.

The fusion of the three cities under a single administration, first enacted by the Hungarian revolutionary government in 1849 but revoked on the subsequent restoration of Habsburg authority, was finally effected by the autonomous Hungarian royal government established under the Austro-Hungarian Ausgleich ("Compromise") of 1867.