'For all his works Michelangelo always made models, but he rectified [his drawings after them] from nature while he proceeded with his work.'

'As we all know, one or two figures in full relief contain an endless number of views and we have just to turn those models round and round in order to find those views and use them in our painting. This one can see specifically in Michelangelo's Last Judgement, where he has employed the method I mentioned above. There are other artists who have their own method concerning the limbs [of wax models]: they dip them into hot water, and when the limbs become soft they can be bent and twisted in any way required.

Leonardo da Vinci, as one of his Milanese pupils has told me, when he once saw such a painting [by Michelangelo] and probably realized what method had been employed, had the audacity to say that this was the only thing that displeased him in this picture because too few figures were used in too many positions, so that the figure of a youth and the figure of an old man had the same muscles and the same outlines.'