Leonardo was called back to Milan in 1506 by the French occupiers of the city, and he served them in a variety of capacities for most of the next seven years. While he did turn his hand to some paintings – most notably the St Anne, possibly for the King of France – he was working more as a designer and scientist.

Leonardo’s intended treatise on painting, begun 20 years earlier, had spawned several distinct strands of investigation – anatomy, optics, water, atmospheric phenomena, the figure in motion and so on, and during his second Milanese period he worked intensively on these fields – none more so than anatomy, the field in which he made his greatest advances.

But once again military strife disrupted Leonardo’s work. The French were ousted from Milan, and in 1513 Leonardo abandoned Lombardy for Rome, under the patronage of Giuliano de’ Medici, brother of Pope Leo X.

After an unproductive couple of years, in late 1516 Leonardo accepted an offer of employment by the French king.