This contribution focuses on a painting by the Sienese Alessandro Casolani (1552-1607) mentioned in the sources but thus far never identified. Isidoro Ugurgieri Azzolini recorded in his detailed biography of the artist (1649) a pala depicting “Saint Alfonso receiving the priestly robe from the Madonna” that had been sent to some unknown Neapolitan destination. The author proposes that the work be identified as the grand pala of such iconography actually in an oratory of the Neapolitan convent of San Domenico Maggiore. The painting comes from the Trecento chapel of cardinal Rinaldo Brancaccio dedicated to Saint Andrew, and almost certainly commissioned by Alfonso Brancaccio at the beginning of the Seicento. Furthermore, the painting, previously attributed to a variety of authors, is in fact signed and dated 1603 by Casolani. The ties between Alfonso Brancaccio and the Sienese Alessandro Turamini, professor of law at the University of Naples, make it a highly plausible hypothesis that the commission came from a descendant of the aforementioned cardinal. On one hand the complex iconography of the canvas evokes the cardinal, particularly due to the presence of Saint Vito, the martyr to whom his diaconal titular church at Rome was consecrated, San Vito in Macello Martyrum. On the other hand, the imagery draws attention to the figures of Saints Ildefonso and Raimondo of Pennafort. Saint Ildefonso's presence recalls the office of the Novena of Christmas, which was introduced in Italy, specifically in San Domenico Maggiore by Father Alfonso da Maddaloni, who for a long time was considered in Neapolitan sources the patron of the painting. Furthermore, we show that the articulated depiction of the iconography is the fruit of complex research as testified by two drawings never before ascribed to Casolani in the Pinacoteca Nazionale and the Biblioteca degli Intronati at Siena.