Founded as a Roman city, Barcelona became the capital of the County of Barcelona. After merging with the Kingdom of Aragon, Barcelona became the most important city of the Crown of Aragon. Besieged several times during its history, Barcelona has a rich cultural heritage and is today an important cultural centre and a major tourist destination. Particularly renowned are the architectural works of Antoni Gaudí and Lluís Domènech i Montaner, which have been designated UNESCO World Heritage Sites. The headquarters of the Union for the Mediterranean is located in Barcelona. The city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments.

Indeed, it is a major cultural and economic centre in southwestern Europe (Iberian Peninsula), 26th in the world (after Moscow, before Dubai)[11] and a growing financial centre (Diagonal Mar and Gran Via). It is the fourth economically powerful city by GDP in the European Union and 35th in the world with an output amounting to €177 billion.[12] As of 2009 the city was ranked Europe’s third and one of the world’s most successful as a city brand.[13] At the same time, the city was ranked Europe’s fourth best city for business and fastest improving European city, with growth improved by 17% per year.

The founding of Barcelona is the subject of two different legends. The first attributes the founding of the city to the mythological Hercules. The second legend attributes the foundation of the city directly to the historical Carthaginian Hamilcar Barca, father of Hannibal, who named the city Barcino after his family in the 3rd century BC.[21]
In about 15 BC, the Romans redrew the town as a castrum (Roman military camp) centred on the “Mons Taber”, a little hill near the contemporary city hall (Plaça de Sant Jaume). Under the Romans, it was a colony with the surname of Faventia,[22] or, in full, Colonia Faventia Julia Augusta Pia Barcino[23] or Colonia Julia Augusta Faventia Paterna Barcino. Pomponius Mela[24] mentions it among the small towns of the district, probably as it was eclipsed by its neighbour Tarraco (modern Tarragona), but it may be gathered from later writers that it gradually grew in wealth and consequence, favoured as it was with a beautiful situation and an excellent harbour.[25] It enjoyed immunity from imperial burdens.[26] The city minted its own coins; some from the era of Galba survive.