Although our knowledge about the methods used to design and proportion large-scale works of art during the Trecento and early Quattrocento is gradually expanding, it still remains fragmentary. Paul Frankl was one of the earliest scholars to speculate on the subject. Based on his assumption that the masons in Europe from the late thirteenth through the early sixteenth century constituted an essentially homogeneous group, Frankl argued that the design and proportional methods of medieval Italian masons must be similar, if not identical, to the ‘secrets’ of the German masons published by men such as Matthäus Roriczer, Hans Schmuttermeyer, and Lorenz Lechler in the late fifteenth and early sixteenth century. Indeed, the so-called Roriczer method, which utilizes irrational but geometrically related lengths generated by a series of inscribed or circumscribed squares, has remained a favored means of explaining Italian medieval and early Renaissance design and proportional procedures since Frankl's time.