In June 1715 Thornhill was officially awarded the much-coveted commission to decorate the dome of St Paul's Cathedral in London, for which he had been competing since 1709 (see Tate L01481). This small oil is one of a set of eight (see Tate L01482-7 and L01489) which probably forms a presentation set painted after the eight scenes from the life of St Paul as finally finished in the cupola. Thornhill strictly adhered to the 1709 and 1715 rulings that the dome be painted with figurative histories taken from the Acts of the Apostles, and that they be executed in monochrome, simulating sculptural relief. Thornhill worked on the cupola until 1717, for which he was paid £4,000, and on other areas of the dome until 1721 (see Tate L01482).
St Paul before Agrippa is the seventh episode in the cycle, which moves anti-clockwise round the dome, starting with Paul's conversion positioned directly to the east. It is taken from Acts 26: 1-29. Paul, a prisoner at Caesaria by the wish of the chief priests and Jewish elders of Jerusalem, was brought to the presence of King Agrippa who wished to hear his case. He explained his conversion on the road to Damascus and, ever since, his unswerving faith in the Lord. Thornhill shows him possibly at the moment when he asks, 'King Agrippa, believest thou the prophets? I know that thou believest', and Agrippa, who holds his hand to his breast, replies, 'Almost thou persuadest me to be a Christian'.
The episode is an unusual one to select, although Thornhill's composition bears a strong resemblance, but reversed, to Raphael's (1483-1520) tapestry cartoon of the Blinding of Elymas (circa 1514-16, Victoria and Albert Museum, London). In preliminary design stages he had also considered using it, with alterations, for his own version of that episode.
Arline Meyer, Sir James Thornhill and the Legacy of Raphael's Tapestry Cartoons, exhibition catalogue, Miriam amd 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.73-4 and 271b