In the age of the Guildford Four you can believe this essentially innocent, if misguided, man could be tried and executed, but such anachronistic mirages (or jokes) only work because of van Dyck's accurate delineation of the man inside the ruler.
Painting and government were closely related in the 17th century. Painters often doubled as diplomats or spies and pictures were a currency of political patronage and exchange. You might therefore expect van Dyck to be a contented salaryman, glorifying the King with skills honed during his early years as a devotional artist. And he has, indeed, stood accused of making his way by glamorising and flattering the illusion of Divine Right. But to me, of all England's court painters, he is the only worthy heir of the shrewdest and most honest of them all, Hans Holbein the Younger. Van Dyck's view of the English court is lit by a Holbeinesque belief that he was dealing with men, not gods - a very different view from that of the virulent royalists who would posthumously recruit the painter to their cause.
Van Dyck's creative path was not always a smooth one. Some sitters complained of his insistent realism, the Duchess of Sussex declaring, "The picture is very ill-favoured, makes me quite out of love with myself, the face is so big and so fat . . . but truly I think it is like the original." Others took issue not with his methods but with his very existence.
Puritans regarded pictures as an abominable offence against the Second Commandment and an incitement to further horrors such as dancing, masquing and adultery. The vigour and potency of van Dyck's work struck them like a shock of forbidden insight. In a land that would soon be stalked by a Witchfinder General, it may even have appeared demonic.
Van Dyck was not deflected by any criticism. Although he was reviled as a foreigner, a "Spaniard" (because from the Spanish Netherlands) and a Papist, plentiful evidence survives of his creative courage in pursuing the art, so despised today, of "official" portraiture. His independence of mind undoubtedly benefited from Charles's support, the King's artistic judgement being far more refined than his political acumen. Both men revered Titian and the humanist art of the Italian High Renaissance, and this sympathy led to genuine friendship between artist and patron, giving certain Caroline portraits by van Dyck a markedly personal atmosphere.
Van Dyck, seeking to locate the balance of strengths and weaknesses in his sitters, and to gauge their humanity against their public roles, was at his best when painting a friend. As Robert Hughes once put it, his portraiture rests on "a diplomatic agreement between truth and etiquette, between private opinion and public mask".
So, it is possible to argue that this great painter was, if only accidentally, a subversive force in the English court. He had a way of depicting royalty which heralded or even, in some way, created a new kind of king: human, fallible, vulnerable - and ultimately disposable. When a rebellion arose strong enough to kill the monarch into whose watery eyes the painter had stared so often and so intently, van Dyck might not have been at all surprised. But, of course, he did not live to see it.
Robin Blake is the author of `Anthony van Dyck: a life 1599-1641' (Constable, pounds 20)Reuse content