London most often denotes the sprawling London metropolis, or the 32 London boroughs, in addition to the City of London itself.This wider usage of London is documented as far back as 1888, when the County of London was created.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.
By the time the London Wall was constructed, the City's fortunes were in decline, and it faced problems of plague and fire.The Roman Empire entered a long period of instability and decline, including the Carausian Revolt in Britain.In the 3rd and 4th centuries, the city was under attack from Picts, Scots, and Saxon raiders.The decline continued, both for Londinium and the Empire, and in 410 AD the Romans withdrew entirely from Britain.Many of the Roman public buildings in Londinium by this time had fallen into decay and disuse, and gradually after the formal withdrawal the city became almost (if not, at times, entirely) uninhabited.Administratively, it forms one of the 33 local authority districts of Greater London; however, the City of London is not a London borough, a status reserved for the other 32 districts (including London's only other city, the City of Westminster).It is also a separate county of England, being an enclave surrounded by Greater London. The 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 km The name London is now ordinarily used for a far wider area than just the City.Archaeologist Leslie Wallace notes that "Because no LPRIA settlements or significant domestic refuse have been found in London, despite extensive archaeological excavation, arguments for a purely Roman foundation of London are now common and uncontroversial." At its height, the Roman city had a population of approximately 45,000–60,000 inhabitants.Londinium was an ethnically diverse city, with inhabitants from across the Roman Empire, including natives of Britannia, continental Europe, the Middle East, and North Africa.About three quarters of the jobs in the City of London are in the financial, professional, and associated business services sectors.The legal profession forms a major component of the northern and western sides of the City, especially in the Temple and Chancery Lane areas where the Inns of Court are located, of which two—Inner Temple and Middle Temple—fall within the City of London boundary. Its bridge over the River Thames turned the city into a road nexus and major port, serving as a major commercial centre in Roman Britain until its abandonment during the 5th century.