There was an influx of foreign-born decorative artists in London in the first decades of the eighteenth century. Antonio Pellegrini, Sebastiano and Marco Ricci, Louis Laguerre and Louis Cheron, among others, were apparently making themselves handy for the much-anticipated commission of the day, the decoration of the newly completed St Paul’s Cathedral. According to a tradition first reported at the end of the century, however, they had no hope. Though ‘no judge of painting’, Archbishop Tenison is said to have insisted, in terms that may recall contemporary immigration rhetoric, ‘first that the painter employed be a Protestant; and secondly that he be an Englishman’. Accordingly, the job went to the only Protestant Englishman available, Sir James Thornhill.

Thornhill is often cited as the beneficiary of such nativist sentiment, to the detriment of his painterly skill. By 1715, the date of the St Paul’s commission, he had already begun work on his biggest project, the ceiling at the new naval hospital at Greenwich (finished in 1726). Ronald Paulson, biographer of Thornhill’s son-in-law, speculates that Thornhill had been chosen primarily because tight-fisted project managers guessed he would be cheaper than his Italian competitor, Antonio Verrio. However, in 1737, the son-in-law in question, William Hogarth, wrote to the St James’s Evening Post that though Thornhill had called in the assistance of ‘a foreigner’ for the figures of the royal family in the hall, ‘with regard to the ceiling, which is entirely of his own hand, I am certain all unprejudiced persons, with (or without) much insight into the mechanical parts of painting, are at the first view struck with the most agreeable harmony and play of colours that ever delighted the eye of a spectator’. With the opening of the painted ceiling tours at the Old Royal Naval College this year, visitors (unprejudiced or otherwise) can inspect it at close quarters, and judge for themselves.

Taken together, Thornhill’s hall and ceiling form the largest decorative scheme in London. Its baroque bombast, which has seen it dubbed ‘England’s Sistine Chapel’, is at odds with the lowly purpose for which it was intended. With its architecture designed by a young Hawksmoor, under the distant supervision of Sir Christopher Wren, the site was first intended as a public charity, a hospital for retired British seamen. So while Thornhill’s Englishness may have made him a cost-effective choice for perennially thrifty civic officials, it also underlined the patriotism of the project. Here, Britain said, was how Britain’s servants were rewarded. The hall was to be the pensioners’ dining room, a place where they could eat surrounded by reminders of Britain’s royal dynasties and global greatness. In this sense, the scheme is Protestant re-interpretation of a traditionally Catholic idiom, echoing, perhaps, the sycophantic ceilings of Charles Le Brun at Louis XIV’s Versailles. William and Mary accordingly appear at its centre crushing a figure of ‘arbitrary or tyrannical power’, said to bear some resemblance to the Sun King himself. Below them, the prow of a splendid vessel juts into view, an implied allegory of Plato’s ship of state (or conquest) but equally a reminder of the erstwhile profession of those eating below. Indeed, Hogarth added an ‘N.B.’ as a P.S. to his letter of 1737, noting, with philanthropic practicality, that ‘if the reputation of the work were destroyed, it would put a stop to the receipt of daily sums of money from spectators’. The work itself seems to be just such a reflection of practicality and idealism.

The ceiling tours now offered by the Old Royal Naval College are the public-facing part of an extensive conservation project part-funded by the Heritage Lottery Fund. Work on the ceiling follows on from the cleaning already undertaken in 2013 on the Painted Hall, and is expected to last until 2019. While it is ongoing, visitors on pre-booked tours can climb the vertiginous scaffolding, ascending to the apotheosis of William and Mary, sixty feet in the air. There is something undeniably perverse about this ascent. It makes visible normally hidden aspects of conservation, but also deposits the visitor some few feet away from the ceiling’s surface. The ‘agreeable harmony and play of colours’ to which Hogarth refers were, of course, intended to be appreciated from the floor. On the ground, the overwhelming grouping of royal bodies, allegorical figures and illusionistic devices might more easily coalesce into the swirling drama and apparently limitless space typical of the baroque.

Yet, as you climb, new vistas unfurl of smaller elements long unnoticed, which, in turn, draw the visitor’s attention to other names and talents largely lost. The gilded wood-carving in the cupola, where high-relief thistles jut against fat pears and soft feathers, was surely nothing to do with Thornhill, but rather the result of creative collaboration with craftsmen and specialists (and probably not English ones either). The baskets of fruit and plenty presented to William and Mary by allegorical deities seem similarly painted by dedicated still-life painters. While, in his rush to defend England’s ‘history painter’, Hogarth may have permitted himself some license when he asserted that the ceiling was ‘entirely of [Thornhill’s] own hand’, it is probable that such joint ventures were simply assumed. In any case, viewing a painting at such close quarters inevitably draws attention to such practicalities. The vastness of the project necessitates it being fundamentally collaborative, but also leaves traces of the hierarchies of the eighteenth-century art world: legions of unnamed craftsmen, and the few named impresario-artists conducting them.

This tension is also reflected in the broader struggle between individual elements and their relation to the whole, a fundamental concern both for the type of monarchy such a scheme celebrates, and of ceiling painting itself. On the ceiling’s viewing platform, neck craned, you come face to face with the royal family themselves. Queen Mary is painted with the portraitist’s care, a calm centre in an otherwise tremulous scheme. Replete with what Pope characterised as ‘the sleepy eye, that spoke the melting soul’, it is a little odd to find this kind of almost mechanical painting horizontal on a ceiling, rather than gilt-framed in a country house, or among the ‘Windsor Beauties’ now hanging in Hampton Court (originally painted by Thornhill’s rival, the Dutchman Sir Peter Lely). This pure portrait painting shows few signs of the perspectival manipulation that characterises Thornhill’s vigorous, smoke-blackened allegory of the Four Winds in the formerly much-overlooked cupola. Yet these more exciting passages of paint return in the more imaginative figures surrounding the royals. Here, the confident brushwork and hyper-extended limbs point to Thornhill’s expert manipulation of the strange angles and perspectives demanded, uniquely, by the viewing conditions of ceiling painting.

As with the collaboration of craftsmen, it feels fitting that as the ceiling is cleaned, it should also call attention to the joint work of later restorers, whose project is, after all, the driving force of these tours. On the ceiling there are traces of varnish and retouchings, but not always anonymous: there are also small bits of graffiti, latter-day maker’s marks. Most flagrantly of all, a name has been scratched into Mary’s décolletage, at the ceiling’s narrative and compositional centre, by a workman who must have counted on his work remaining forever unseen from the floor. Seen from feet away, it leaps immediately to view, calling attention to the obvious, yet usually unacknowledged point—central to this spectacular viewing opportunity—that what we see beneath is only ever a small portion of the total labour above.

Ceiling tours at the Old Royal Naval College began on 1st April 2017 and are ongoing. Prior booking is recommended.