岩窟の聖母
The subject of two Infants kissing was an inspirational source of quite a few (about thirty) copies of pupils and followers of Leonardo da Vinci. An early sketch of the subject by Leonardo himself is held at Windsor in the Royal collection. The sheet shows various studies of Madonna and Baby playing with the cat, while at the very bottom we see two infants kissing and embracing each other. The sketch is quite different from the version presented at numerous compositions, while the baby on the right is shown in a very same pose as Jesus in "Virgin of the Rocks".