Agnolo Gaddi (active from 1369-1396), Heads of Five Youths and Lamb’s Head, circa 1380, pen, paintbrush and bistre on parchment, 196x160 mm (inv. n. 2787/4 B 1021 bis, recto)

One of the oldest drawings of the Sforza Castle collection, the study of the heads of five youths, is actually the study of the same face reproduced five times in different poses and examined from different angles. The heads, gathered on the front of the parchment, are drawn in natural poses, taken from everyday life, and are early examples of naturalism in portraiture. On the same sheet, at the top centre, is the drawing of the head of a lamb, under which is written "agnius" and a sign interpreted as the monogram of Christ's name or as the letter "P", a possible abbreviation of the term " pictor ". On the back of the parchment, an additional drawing represents two monks and a woman bending down.
The most reliable hypothesis, based on the typology of the male figures and their similarity with those the artist frescoed in the choir of Santa Croce in Florence, attributes the authorship of the parchment to Agnolo Gaddi, dating it to the 1380s. The study has also been considered to be the work of Ambrogio Lorenzetti, due to its resemblance with his frescoes in the Basilica of San Francesco in Siena, bringing forward the execution of the work to the 1330s or 1340s. Another interpretation attributes the folio to a Florentine artist active in the 1420s and belonging to the generation of Cennino Cennini, who in his Treatise on Painting, stressed the importance of "portraying the natural."