It is one of the oldest drawings in the Sforza Castle Collection. Studies of five heads of young people, or rather of the same face reproduced five times in different attitudes and examined from different points of view, are gathered in the recto of the parchment. Described with great naturalness, the faces are taken from life, as early examples of natural portraits. On the same sheet, at the top and in the center, the head of a lamb is drawn, under which is written "agnius" and a sign interpreted as the monogram of the name of Christ or as the letter "P", presumed abbreviation of the term " pictor ". On the reverse of the parchment, another drawing represents two monks and a bent woman. The most accredited hypothesis recognizes the authorship of the sheet to Agnolo Gaddi, with a dating to the 1880s, due to the strong similarity of the male types with the figures that the artist frescoed in the choir of Santa Croce in Florence. The work was also compared to Ambrogio Lorenzetti, in particular to his frescoes in the basilica of San Francesco in Siena, thus anticipating its execution to the third or fourth decade of the century. Another interpretation suggests assigning the sheet to a Florentine artist active in 1420, belonging to the generation of Cennino Cennini who in his Treatise on Painting had emphasized the importance of "portraying the natural".
