This oil sketch, together with St Paul Preaching at Athens (Tate L01480) and another sketch, St Paul before Agrippa (Yale Center for British Art), are preliminary ideas for the decoration of the dome of St Paul's Cathedral in London. One of the most important and sought-after painting commissions of early eighteenth-century England, the task was officially awarded to Thornhill in June 1715 but only after intense competition and changes of mind. The committee in charge of the project, which was headed by the Archbishop of Canterbury and whose other members were ecclesiastics and other professionals appointed by the monarch, had been deliberating the matter since April 1708. The French artist Laguerre (1663-1721) is said to have begun painting, only for work to be halted a month later. Then, in 1709, an open competition was announced. By 1710 the field had narrowed to two contestants, Thornhill and the Venetian, Pellegrini (1675-1741), but no immediate decision was taken.
Decisions regarding the dome seem to have been directly affected by the political composition of the committee, which was ever-changing according to whether the Whig or Tory parties were in power. Thornhill was finally commissioned by a Whig and broadly Low Church-dominated committee who strictly adhered to allowing only figurative painting of an instructional nature. It was when the Whigs had gained power in 1709 that Laguerre's Tory-commissioned work had been discontinued and a competition announced. The new committee had explicitly directed that the dome 'be painted with figures, but confined to the Scriptuall History taken from the Acts of the Apostles' (minute book, St Paul's Cathedral Library). The Acts were particularly fitting as they were regarded as scripturally pure, truthful narratives of early Christianity, scenes from which would act as moral and virtuous exemplars.
Thornhill adhered to the committee's stipulation by electing to divide the dome into eight segments, each dealing with a stage in the life of St Paul. This particular sketch, Paul before Sergius Paulus (Acts 13: 9-11), probably dates from the time of the competition in 1709, when the Committee asked for designs to be submitted by April, or a stage later, in 1710, when Thornhill had to make further designs in direct competition with Pellegrini. The treatment of the subject is very different from that finally painted (see Tate L01483). It relies heavily on Raphael's tapestry cartoon depicting the same moment in the narrative, the blinding of Elymas, which Thornhill had obviously studied in depth. In the early eighteenth century Raphael's tapestry cartoons of the Acts of the Apostles, then hanging at Hampton Court (now at the Victoria and Albert Museum, London), were hailed as supreme examples of painting, both for purity of style as well as dignity of subject matter, and were obvious precedents for Thornhill to look to for guidance and inspiration.
Arline Meyer, Sir James Thornhill and the Legacy of Raphael's Tapestry Cartoons, exhibition catalogue, Miriam and Ira D. Wallach Art Gallery, Columbia University in the City of New York, 1996
Carol Gibson-Wood, 'The Political Background to Thornhill's Paintings in St Paul's Cathedral', Journal of the Warburg and Courtauld Institutes, vol. 56, 1993, pp.229-37
Edward Croft-Murray, Decorative Painting in England 1537-1837, I, London 1962, pp.71-4 and 271b