... already having with all diligence the worthy book of pictures and human movements put an end ...: this passage is one of the first testimonies of Leonardo's work on his Book of Painting and is found in the letter addressed by Luca Pacioli to Ludovico Sforza printed in the "Pars prima" of his Divina Proportione. Pacioli was a friend of the "compatriot" Leonardo and met him in Milan in 1496 when he was called by Duke Ludovico il Moro to teach public mathematics. When he compiled the Divina Proportione, which originated, as we learn from the dedication of the work, from the scientific conversations of that brilliant environment that was the court of Ludovico il Moro and to which Leonardo also belonged, he felt the need to complete it with figures necessary geometries and made use of the very skilled hand of Vinci, whose original drawings he personally kept with him to exhibit them for the admiration of visitors.