London is the capital and largest city of England and the United Kingdom (UK). It is Britain's most populous and Europe's second most populous metropolitan area. A major settlement for two millennia, its history goes back to its founding by the Romans, who called it Londinium. London's core, the ancient City of London, or the 'square mile' financial district, largely retains its mediaeval boundaries. Since at least the 19th century, the name "London" has also referred to the metropolis developed around this core. In modern times, the bulk of this conurbation forms the London region and the Greater London administrative area, with its own elected mayor and assembly.