It is not known how William Adam became a successful architect from these beginnings, but by 1721 he was engaged on major projects at Floors Castle, where he executed a design by Vanbrugh, and designing extensions to Hopetoun House. John Gifford links Adam's rise with the retirement of James Smith, the most prominent architect of the early 18th century, who was in his 70s by this time. Like Smith, Adam was a trained mason, had social connections through his family, and had the financial backing of successful business ventures. It was in 1721 that Adam became a Freemason being initiated in The Lodge of Edinburgh (Mary's Chapel), No.1.