Recommended by Marchese Enzo Bentivoglio to Gregory XV, the Bolognese Ludovisi Pope, Guercino spends two very productive years in Rome from 621 to 1623.

From this stay date his frescoes of Aurora at the casino of the Villa Ludovisi and the ceiling in San Crisogono (1622) of San Chrysogonus in Glory; his portrait of Pope Gregory (now in the Getty Museum, and, what is considered his masterpiece, The Burial of Saint Petronilla or St. Petronilla Altarpiece, for the Vatican (now in the Museo Capitolini).