Haydn is looking well — in fact, he’s positively glowing. The dignified pose; the modest, intelligent smile: it’s only when you squint closely at the portrait that Thomas Hardy painted in London in 1791 that you clock the full peachy-pink smoothness of his complexion. It’s curious, because Haydn suffered disfiguring smallpox as a child, and a contemporary waxwork bust in Vienna is cratered like a moon in a periwig.