space, took relief sculpture to previously unimagined heights.
The period began with the competition for the commission to create the East (later North) doors of the Florentine Baptistery and ended with the designs for Ghiberti's second set of doors, which were created over the next two decades. In that time the changes in Ghiberti's approach alone make it clear how important the revival of the antique had become. Not all relief sculpture of the 1400-30 period was concerned with experiments in perspective but the most important works, including reliefs by Donatello, Ghiberti, Luca della Robbia (c. 1399-1482) and Nanni di Banco (c. 1385-1421), took part to some degree in the application of antique ideals and source materials to contemporary sculpture.
The reasons why sculpture took the lead over painting in the revival of the antique are, apart from the obvious lack of extant classical painting, still debated. Most likely, however, it was due to the fact that painting was largely limited to religious contexts while sculpture "was frequently a public and hence a civic art" (Greenhalgh 75). This certainly coincides with the general view of the flourishing schools of Humanism in Florence and Padua who looked on the revival of antique learning and art more as a source of ethical, civic, and social models than as a source of aesthetic inspiration. The latter was, of course, a principal means of conveying the former and even the assigned subject for the competition for the Baptistery doors (1401-1403), the sacrifice of Isaac, may have had civic connotations. Hartt suggests that the sudden deliverance of Isaac may have referred to the sudden deliverance of Florence caused by the death of Giangaleazzo Visconti, with whom the city was at war. Such a "last-minute personal intervention on the part of the Deity" might well have intended as a subliminal theme of the contest entries (Hartt 127). If so, this would further explain the so...