The area remained rural until London's westward expansion reached Bayswater in the early 19th century. The Ladbroke family was Notting Hill's main landowner, and from the 1820s James Weller Ladbroke began to develop the Ladbroke Estate. Working with the architect and surveyor Thomas Allason, Ladbroke began to lay out streets and houses, with a view to turning the area into a fashionable suburb of the capital (although the development did not get seriously under way until the 1840s). Many of these streets bear the Ladbroke name, including Ladbroke Grove, the area's main north–south axis, and Ladbroke Square, London's largest private garden square.