The City of London, widely referred to simply as the City, is a city, ceremonial county and local government district that contains the ancient centre and constitutes, alongside Canary Wharf, the primary central business district (CBD) of London and one of the leading financial centres of the world. It constituted most of London from its settlement by the Romans in the 1st century AD to the Middle Ages, but the modern area named London has since grown far beyond the City of London boundary. The City is now only a small part of the metropolis of Greater London, though it remains a notable part of central London. Administratively, the City of London is not one of the London boroughs, a status reserved for the other 32 districts (including Greater London's only other city, the City of Westminster). It is also a separate ceremonial county, being an enclave surrounded by Greater London, and is the smallest ceremonial county in England.
The City of London is known as the Square Mile, as i