The present essay aims to define the origin of the debated 'Lamentation of Christ', frescoed by Perino del Vaga in the Roman church of Santo Stefano del Cacco, through the recovery of evidence that enables us to better comprehend Vasari's account, drawing attention to its topographical rather than chronological nature. What emerges is a dating for the 'Lamentation' immediately subsequent to Perino's first works on the vault of the Cappella del Crocifisso in San Marcello al Corso. The clarification of the chronology is important for its implications in the reconstruction of the painter's activity during the delicate years between Raphael's death and the Sack of Rome.