In 1754, John Potter, who had been rated (i.e. paid property tax) for the theatre since its opening, was succeeded by John Whitehead. In 1758 Theophilus Cibber obtained from William Howard, then the Lord Chamberlain, a general licence under which Foote tried to establish the Haymarket as a regular theatre. With the aid of the Duke of York he procured a royal licence to exhibit plays during four months in each year from May to September during his lifetime. He also bought the lease of the theatre from Potter's executors and, having added to the site by purchasing adjoining property, he enlarged and improved the building which he opened on 14 May 1767, as the Theatre Royal, the third patent theatre in London. Several successful seasons followed, with Foote producing numerous plays at the theatre, but Foote finally got himself into difficulties by his custom of caricaturing well-known persons on the stage and this, combined with increasing ill-health, resulted in his selling both the theatre and patent to George Colman Sr. on 16 January 1777.