They were men of a like temperament, and governed by kindred aesthetic instincts.
Michelangelo brought to its perfection that system of working wholly through the human form which Signorelli initiated.

He shared his violence, his _terribilita_, his almost brutal candour.

In the fated evolution of Italian art, describing its parabola of vital energy, Michelangelo softened, sublimed, and harmonised his predecessor's qualities.

He did this by abandoning Luca's naivetes and crudities; exchanging his savage transcripts from coarse life for profoundly studied idealisations of form; subordinating his rough and casual design to schemes of balanced composition, based on architectural relations; penetrating the whole accomplished work, as he intended it should be, with a solemn and severe strain of unifying intellectual melody.
Viewed in this light, the vault of the Sistine and the later fresco of the Last Judgment may be taken as the final outcome of all previous Italian art upon a single line of creative energy, and that line the one anticipated by Luca Signorelli.

In like manner, the Stanze and Loggie of the Vatican were the final outcome of the same process upon another line, suggested by Perugino and Fra Bartolommeo.
Michelangelo adapted to his own uses and bent to his own genius motives originated by the Pisani, Giotto, Giacopo della Quercia, Donatello, Masaccio, while working in the spirit of Signorelli.