City of London skyline,from Leadenhall Street,offices,skyscrapers,architecture, at dusk,London,England,UK,EC3A 8BN

The City of London is a city, ceremonial county and local government district that contains the historic centre and the primary central business district (CBD) of London. It constituted most of London from its settlement by the Romans in the 1st century AD to the Middle Ages, but the modern city named London has since grown far beyond the City of London boundary City of London is widely referred to simply as the City (differentiated from the phrase "the city of London" by capitalising City) and is also colloquially known as the Square Mile, as it is 1.12 sq mi (716.80 acres; 2.90 km2) in area. Both of these terms are also often used as metonyms for the United Kingdom's trading and financial services industries The City is a major business and financial centre, and the Bank of England is headquartered in the City. Throughout the 19th century, the City was the world's primary business centre, and it continues to be a major meeting point for businesses. London came top in the Worldwide Centres of Commerce Index, published in 2008. The insurance industry is focused around the eastern side of the City, around Lloyd's building.