The theme of the Calumny of Apelles is best known within art for the fresco depiction by Sandro Botticelli He was one of the key members of the Italian Renaissance and although Bruegel was also highly significant within the Northern Renaissance, as this artwork is a drawing it is never seen at the same level as a complex tempera, layered, painting.
From the attire, to the interior architecture, this classical depiction is so out of sync with the rest of Pieter Bruegel's paintings and drawings that the question of correct attribution has to be raised. The medium in terms of ink and pen with paper is certainly in line with Bruegel's contributions and the formation of the figures in this piece are also fairly faithful to his own style.
Most of the drawings produced by Bruegel were around the same size, approximately 30cm wide by 20cm tall. This is likely to be because he was working from a sketchbook which would later be divided up into individual sketches and sold on. By having the notebook he would be able to carry it around with him and also compare previous sketches very easily.