Stowe include the pair of "Boycott Pavilions", which were altered by Giovanni Battista Borra in 1754 to replace the pyramidal stone roofs with more conventional domes. Churches Gibbs designed one church for the Commission for Building Fifty New Churches, St Mary le Strand. Construction began in 1714 and it was complete by 1717. Between 1721 and 1726 Gibbs designed his most important and influential work, the church of St Martin-in-the-Fields, located in Trafalgar Square, London. Gibbs' initial radical design for the commission was for a circular church, derived from a design by Andrea Pozzo; its illustration in Gibbs' book was to influence several adaptations by Neoclassical architects. This was rejected by the commission, and Gibbs developed the present rectangular design. The layout and detailing of the building owes much to Wren, in particular the church of St James', Piccadilly. However, Gibbs' innovation at St Martin's was to place the steeple centrally, behind the pediment. By contrast, Wren's steeples were usually adjacent to the church, rather than within the walls. This apparent incongruity was criticised at the time, but St Martin-in-the-Fields nevertheless became a model for church buildings, particularly for Anglican worship, across Britain and around the world. At the same time, Gibbs designed a chapel of ease for the 1st Earl of Oxford, now known as St Peter, Vere Street (1721–24). In 1725 he designed All Saints', Derby, now Derby Cathedral, on similar lines to St Martin's, although at Derby the original gothic steeple was retained. Gibbs, the first British architect to do so, created numerous designs for funeral monuments, often collaborating with the sculptor Michael Rysbrack. In 1733 Gibbs was commissioned by Lord Foley to adapt the chapel from Cannons House (Gibbs was one of the architects involved in designing Cannons), as the parish church at Great Witley. St Bartholomew's Hospital In 1723 Gibbs was appointed a governor of St Bartholomew's Hospital, which led to him being commissioned to redesign the hospital. In 1728 he produced a design with four near identical blocks around a square ; he gave his services for free. The first block to be built, the north, administration block was constructed from 9 June 1730, using Bath Stone (this would be used for all the blocks). It was finished in 1732 and contains the Great Hall and the main staircase, the walls of which are covered by murals painted by William Hogarth, depicting Christ healing