The Four Seasons in Florence is famous for its 12 bas-reliefs by Bertoldo di Giovanni
, one of Michelangelo's teachers, dating from 1555.
It was a pet theory of Middeldorf's that the sculptor Bertoldo di Giovanni
was the illegitimate child of Giovanni de' Medici: he would certainly have been pleased with the discovery, announced in this volume (and published in full in the Institut's Mitteilungen in an article Boninger coauthored with Luca Boschetto), that Bertoldo was instead a German.
The author discusses Lorenzo's principal sources of inspiration, including family tradition, trips taken to Italian courts, ancient and modern literature, and, most strikingly, relationships initiated in early youth with architects, engineers, and artisans, including masters like Giuliano da Maiano and Bertoldo di Giovanni