Portman Square was the focus of the new estate and was followed by the building of Manchester Square during the 1770s and Bryanston and Montagu Squares 30 years later. These were laid out by the Estate’s architect, James Thompson Parkinson. The area remained largely residential, attracting the prosperous middle class who wanted to live near the centre of London. There were also mews for tradesmen and servants. At the southwest corner of the Estate, where Marble Arch now stands, was the Tyburn gallows, London’s principal place of public execution until 1783.