Leonardo da Vinci, a master of ‘sfumato’, described the painting technique as “without lines or borders, in the manner of smoke or beyond the focus plane”.

The detail above is from Andrea Mantegna’s Parnassus in which he makes several references to Leonardo, the sfumato technique being one. Here we see the smoke drifting from the side of the mountain in the direction of the Cupid figure.

But Mantegna amplifies the connection to Leonardo by applying the transition effect of the smoke to form a soft and partial image of the polymath’s head, notably an eye and his mouth. To see this the painting has to be rotated 90º.

At this angle we can see Leonardo has his eye on the Cupid figure. It is meant to represent a young boy who forms part of a relief scupture known as the Madonna of the Stairs (c.1491), an early work by Michelangelo when he was about 15 years old.

Mantegna also matches the boy appearing to have a shortened leg, the effect of climbing stairs. The steps in Mantegna’s version are created by the rocky indents, profiled to suggest the facial features of a lion – and another reference to Leonardo.

Step by step, Michelangelo became the new sensation in Florence, while Leonardo, the god of transitions, moved out beyond the focus plain of Florence and headed North to Milan for a new beginning.

Transition is a major theme of Mantegna’s Parnassus painting.