You can never truly complete a great work of art – this forgotten Renaissance master shows why

When is a masterpiece “by” an Old Master, and when is it not? Over centuries, can a Renaissance altarpiece, say, be left unfinished at its creator’s death, completed by somebody else, sawn into pieces and brought back together again, with sections reconstructed from scratch based on preparatory drawings, and still “belong” to the master?

You may not have heard of the 15th-century painter Francesco Pesellino – which is part of the point of the National Gallery’s ­exhibition Pesellino: A Renaissance Master Revealed. A pioneer of that lush, bold, quattrocento Florentine style, and an influence on better-known figures such as Botticelli, Pesellino has been called “the ­Giorgione of Florence” – not just for his impact on those who came after, but also because he died of plague just as his powers were beginning to peak (Pesellino was 35; the Venetian Giorgione also died in his 30s).

As with Giorgione, only a small number of works by Pesellino survive. But unlike Giorgione, what remains inspires no great mystique. Giorgione’s portraits of noblemen seem to beam the essence of the human condition to us from early-modern Venice, whereas Pesellino was best-known as a painter of animals: his figures are wonderfully posed, right down to the testicles on the horses, but they remain essentially symbols.

And while it can be difficult to authenticate a Giorgione, we might at least imagine the works attributed to him in galleries bear the mark of some incomparable master. But it is an unavoidable fact that Pesellino’s altarpiece The Trinity with Saints – the show-stopper at the centre of the National Gallery exhibition – was cut up and later put back together with additions by restorers, after having been finished by another hand (Pesellino’s sometime teacher, Fra Filippo Lippi) when it was left incomplete at the time of Pesellino’s death in 1457.

Exactly how far from finished the Trinity altarpiece was when Pes­ellino died can’t be known with certainty – but we know that the extent to which it was finished mattered at the time. The altarpiece had been commissioned in 1455 for a chapel in Pistoia, Tuscany, by priests who had a budget of 200 florins, a considerable sum. After Pesellino died, his widow sued his former business partner for his cut of the pay, asserting that the altarpiece had been mostly complete – Lippi’s workshop, by contrast, estimated that it was only halfway there.

Nowadays, I am told by Jill Dunkerton, paintings conservator at the National Gallery, we are able to get a good sense of the veracity of these competing claims by examining the main panel using infrared light, which reveals Pesellino’s under-drawing: we see that the finished panel cleaves very closely to his plans. By contrast, the same method suggests that the panels on the predella – the altarpiece’s bottom tier – were almost entirely done by Lippi’s workshop. In a way, both Pesellino’s widow and Lippi’s workshop were correct – Pesellino had indeed almost completed the altarpiece, if by the altarpiece you mean the main panel; but in terms of the work overall, there was still about half of it left to be done.

Lippi would have been an obvious candidate to complete the commission after Pesellino died: Pesellino had been employed in Lippi’s workshop earlier in his career; they had collaborated on commissions in the past. But Pes­ellino was a “control freak”, who would plan obsessively and was, by this stage, mostly working alone: one reason why his commissions tended to proceed slowly. 

Pesellino was also a remarkably logical painter, Dunkerton tells me. And if you look closely at the main panel, you can spot “illogicalities”, or areas that aren’t quite mapped out with his customary precision – which point to the involvement of Lippi. Christ on the cross, for instance, has finely detailed hands, but God’s hands are a bit of a fudge by comparison, and fail to give a sense of the cross’s weight.

Is the Trinity altarpiece a lesser work for not bearing the full mark of Pesellino? When I put this question to Dunkerton, her answer is an immediate and emphatic, “No!” Lippi was a “much less logical” artist than Pesellino, she says. But you have to really look for the “illogicalities” to see them – and they were both “wonderful” painters, regardless. The altarpiece is also a testament to a student-teacher relationship that helped to shape Florentine painting in this period.

This speaks to its historical ­significance. Pesellino was no Raphael. The Trinity altarpiece is a magnificent work, but from an art-historical perspective, it is less important in itself than as a tran­sition to something else – an “astonishingly inventive and influential” work, in Dunkerton’s view, full of elements by which Pesellino’s Florentine successors would be guided. The altarpiece belongs to, or mostly belongs to, the neglected master Pesellino. But it also belongs to a specific moment in Florentine art. Perhaps a city can be an author, too.

There is a lesson here, when it comes to works left unfinished at the time of their creator’s death. There are two broad schools of thought – at least when it comes to publishing or displaying them (one could also just destroy them, or let them languish in some archive). The first is that the works should be released as they are, in whatever fragmentary state the departed genius has left them. The second is that they should be fixed up, afforded some semblance of completeness, in accordance with what (from studying diary entries, for instance) we can infer were the artist’s probable intentions.

In the first camp we have Max Brod publishing Kafka’s incomplete novels (famously against his late friend’s stated instruction, which was that Brod destroy them); and Robert Musil’s endless modernist masterpiece The Man Without Qualities, published editions of which often incorporate the author’s drafts, notes, and various false starts. In March 2024, an unfinished manuscript by Gabriel García Márquez – who died in 2014 – will be published as “the lost novel”, despite the author’s wishes that the work never see the light of day.

Meanwhile, in the second we have Beethoven’s once-hypothetical 10th Symphony, assembled in 1988 by the Beethoven scholar Barry Cooper from his study of the composer’s sketchbooks. And Jane Austen’s Sanditon, of which various “completed” versions exist (including, most recently, a three-series TV period drama adaptation by Andrew Davies). Perhaps in this category we might also count volumes two and three of Marx’s Capital, completed by Engels after his death.

The first approach prioritises a fidelity to the authenticity of the artwork, and is not willing to sacrifice it in service to the production of a recognisably “complete” work. The second prioritises the creation of a finished work, and is willing to risk riding roughshod over the author’s intentions in order to bring such a work into existence. 

Any editor, or continuator, must be guided by the condition in which they find the unfinished work, as well as its original purpose. And sometimes, art for art’s sake might be beautiful even if left unfinished. You can appreciate the imperfect charm of the 19th-century portrait of an Austrian military officer, reproduced below. Or consider the version of Manet’s The Execution of Emperor Maximilian, salvaged from fragments by Degas, which now hangs in the National Gallery. But the priests of 15th-century ­Pistoia would never have stood for an unfinished altarpiece. It makes sense to provide an Austen romance with a satisfactory conclusion; but it would seem like someone had missed the point of Kafka if they tried to weave a traditionally complete whole out of The Trial. Beet­hoven’s notes, meanwhile, would never have added up to a symphony without a major intervention.

But it is in their failure, rather than their success, to meet any pre-ordained standard of completeness that the true value of such posthumous works lies. Whether completed, like Pesellino’s altarpiece, or left deliberately fragmented, such works remind us that (for all the art market might pretend otherwise, in its effort to shore up ever more obscene prices) any work of art is likely the product of multiple authors, or at any rate is always open to intervention, whether from editors, restorers, translators, critics or even readers. To cite a famous philosophical puzzle, Plutarch’s “Ship of Theseus” (if every plank is eventually replaced to stop the ship from simply rotting away, is it still Theseus’s vessel?), a ship can have more than one shipwright.

The meaning of a work can change: it is in being appropriated, referenced, sampled and bastardised that art lives on. The greatness of Shakespeare lies not only in how wonderful his plays are, but in how they have shaped, and continue to shape, literature, popular culture and language beyond them. Or think of how the painter Elías García Martínez’s pedestrian fresco Ecce Homo (1930) for a church in Borja, Spain, became internationally famous only after it was accidentally transformed by the octogenarian parishioner and unqualified restorer Cecilia Giménez into the so-called “Monkey Christ” in 2012.

Great works are not immediately and eternally great – the sole product of some transcendent genius. Great works are the product of their time, in which many people of less-than-genius were working; individuals who were contemporaries of, who collaborated with, who inspired or informed or imitated those we recognise as “true” greats; who pushed things forward in their own way. Great works are significant because of what we can do with them: how we might build on them, or transform the works, today. This, surely, is the whole point of “rediscovering” a painter such as Pesellino. The beauty and the brilliance of art lie in the promises it has not quite realised yet.

Pesellino: A Renaissance Master Revealed is at the National Gallery, London WC2 (nationalgallery.org.uk) from December 7 to March 10