Dating Leonardo's early works, or proving authenticity, is particularly difficult. This picture was probably painted somewhere between 1475-1480 when it is recorded that Leonardo produced several Virgin Marys, though it has been heavily over painted since that time. A note made by Leonardo on a drawing suggests that the Benois Madonna may be one of two Virgins started in the final months of 1478, the other being the Madonna with the Carnation. Even though Leonardo was still at Verrocchio's workshop these may be the first figures he conceived and realised in total independence from his master.
In any work attributed to Leonardo it is necessary to examine what may make the piece doubtful. With Benois Madonna it is in details like the ears which are simply too inaccurate for a man who paid an almost meticulous attention to anatomy. The Child almost floats in the lap of the Virgin while her smile is almost impressionistic, not typical of Leonardo. Also lacking is the fine attention to the draperies and one might query why there is no landscape through the window.