Not only do Denys Calvaert's paintings and drawings often featurc duplications of compositions or parts of compositions; figures and indeed entire compositions in mirror image repeatedly occur. In his drawings the artist made use of the counter-proof; he drew on the front and back of the paper, experimenting with various techniques and styles. Some of Calvaert's extant drawings were evidently intended as instructional material for pupils. He is known to have been the first artist to run an academy in Bologna. Drawings with indications of proportions, and a copy in which the model has been corrected, undoubtedly belonged to the teaching material in Calvaert's academy. He may have demonstrated mirror-image repetition in a different technique to his pupils as an aid to preparing a composition, a procedure which he himself had doubtlessly employed before.