The 18th century was a period of rapid growth for London, reflecting an increasing national population, the early stirrings of the Industrial Revolution, and London's role at the centre of the evolving British Empire. By the end of the century nearly one million people lived in London, about one tenth of the population of Great Britain. By 1715, London's population reached an estimated 630,000 people, roughly equaling that of Europe's largest city until that time, Paris. Within a few years London itself was the largest city in Europe, reaching 750,000 people by 1760 and 1 million by the end of the century. Extent and population London's growth in the 18th century was marked above all by the westward shift of the population away from the City of London. Westminster was intensively developed, with new districts like Mayfair housing Britain's wealthiest aristocratic families. To the north of Oxford Street, the building of Cavendish Square in 1717 on the estate of Lord Harley inaugurated the development of the eastern half of Marylebone, while the Portman Estate, which occupies the western half of Marylebone, began its own building program in the 1750s with the granting of commercial leases, followed by the commencement of building on Portman Square in 1764. The most exclusive area, Mayfair, was intensively built up with luxury townhouses on an area occupied by seven different estates: the Grosvenor, Burlington, Berkeley, Curzon, Milfield, Conduit Mead, and Albemarle Ground estates. The Grosvenor estate, in the northwest corner between Oxford Street and Park Lane, was the most substantial private plot of land, featuring an orderly grid network of streets constructed around Grosvenor Square in the early 1720s. By 1738 "nearly the whole space between Piccadilly and Oxford Street was covered with buildings as far as Tyburn Lane [Park Lane], except in the south-western corner about Berkeley Square and Mayfair". Rural villages surrounding Westminster and the City also grew in population and were gradually incorporated into the metropolis: areas like Bethnal Green and Shadwell to the east, or Paddington and St Pancras to the northwest. In 1750 the London topographer John Noorthouck reckoned that London proper consisted of 46 former villages, two cities (Westminster and the City of London proper), and one borough (Southwark). Westminster had a population of 162,077, the City 116,755, and Southwark 61,169. Urban fabric To accommodate the rapid growth of population, Parliament enacted building legislation and initiated important infrastructure projects.