According to the Getty Museum website:
In this series of twenty drawings, Federico Zuccaro illustrated the early life of his older brother Taddeo Zuccaro, from the hardships of his early training in Rome until his first artistic triumph at the age of eighteen. In addition to the sixteen scenes from Taddeo’s life, the series includes four drawings of allegorical Virtues flanking the Zuccaro emblem. The drawings vividly convey a sense of the artist’s material and intellectual life in Renaissance Rome. Details of studio practice join depictions of precise locations, monuments, and antiquities and references to the great artistic personalities of the Renaissance, including Michelangelo and Raphael. Scholars believe that the shape of the drawings shows that they were studies for decorative ceiling panels. Because so many of the sheets contain images of Rome, they may have been intended for frescoes in the Palazzo Zuccari in Rome. In Federico’s will of 1603, he left his palazzo to the Accademia di San Luca so that it could be used as a hostel for poor, young artists coming to study in the capital. The imagery of Taddeo’s early struggles would have been an appropriate reminder for the students at the beginning of their careers.