The article summarizes a research that compares the preparatory drawing highlighted by the reflectography on the painting of the Pietà di Ragusa attributed to Michelangelo, with a definitely drawing of the Florentine master, the Punishment of Tizio made for Tommaso Cavalieri after 1534. The possibility of comparing two homogeneous artworks, in essence two drawings of the same dimensions, allows a congruous evaluation of the stylistic and graphic details that unite them. This comparison, made possible by modern diagnostic investigation techniques, is an important foundation for authenticating the painting. The research aims to underline how scientific investigations conducted on artistic artifacts are changing the History of Art, giving a more objective foundation to critical hypotheses and expanding the field of investigation by the collection of new material data. This evolution of research is intended to correct and revise many critical hypotheses based more on the authority of tradition than on scientific grounds.