On this sheet Leonardo drew three separate sequences of mountains on the horizon, one above the other; at the centre are the peaks of the Grigne, near Lecco in the foothills of the Alps, as seen looking north from Milan – perhaps from the roof of the Duomo or a tower of the Castello Sforzesco. This is an extraordinary depiction of strong sunlight falling on mountains and seen at a distance through clear atmosphere. A companion sheet (RCIN 912414) bears a note on these effects:

   The rocks of this mountain take on naturally a colour
   tending towards blue, and the intervening air makes
   them appear bluer still, particularly in the shadows.
   They also show dark marks from the minute trees
   which grow among them, and have in their dividing
   lines an ochre tone and violet-coloured marks. Outlines
   of a white tone are stone quarries, and among
   them are thick woods interspersed with meadows.

Text adapted from Leonardo da Vinci: A life in drawing, London, 2018