FONTES 47 publishes two sixteenth-century iconographical texts for Giorgio Vasari’s cycle of paintings in the Palazzo Vecchio in Florence: (1) Cosimo Bartoli’s "invenzione" for the Castration of Caelus, and (2) Giorgio Vasari’s description of his painting based on this invention. Vasari’s "Castration of Caelus" constitutes the central work of the upper level of Vasari’s decoration in the Palazzo Vecchio, the Quartiere degli Elementi. An essay examines the consequences of the iconographical invention for the visual appearance of the painting