Calder on the influence of Proclus on John Dee

Now, although many early neo-Platonists such as Plotinus (who praises for instance the way the Egyptian sages have expressed the true natures of each thing in the hieroglyphs standing for them (86)) or Iamblichus, dealt with the virtues of figures from this point of view, it is Proclus who offers some of the fullest, most explicit discussions, and the most obviously relevant to Dee's present work. He recurs frequently to the theme, seeming to regard the best method in all instruction to be that which he attributes to the Pythagoreans, which falls into three stages (perhaps corresponding to the familiar levels of Sensible Intuition, Abstract Reason, and Spritual Reality) the first and third of which employ this approach. For prior to scientific doctrine the Pythagoreans render manifest the proposed objects of enquiry by approximate similitudes and images, and finally once more have recourse to symbols of a different kind to reveal the arcane virtues of these objects (87). In the preface to his commentary on Euclid, a work in which Dee seems to have been thoroughly steeped, Proclus declares that in Numbers, Figures and Musical Accords are to be found the three ways in which the constitutive reasons of all intellectual, moral and theological truths are presented to the human mind, and later has a lengthy discussion on the virtues of figures reflecting directly on the position taken up in Dee's Monas
http://www.johndee.org/calder/html/Calder6.html