The two paintings were donated as an inheritance to the collegiate church of Santa Maria in Via by Cardinal Angelo Giori, (+1662), who not only erected at his expense, splendid and fragile, the temple of S. Maria in Via, but wanted to enrich it with apparatuses uncommon: in particular to the beautiful altarpieces he added, as a treasure of the Sanctuary, a picture gallery for the sacristies. Thus we read in the testament of Cardinal Angelo Giori left on January 2, 1655 in the Church of Santa Maria in via di Camerino: "the painting of San Giovanni Battista and S. Girolamo large in life, made by Monsù Valentino". They can be traced back to Valentin's artistic maturity when he painted for Cardinal Francesco Barberini or through his mediation. It is known in fact that the prelate Angelo Giori was very attached to the Barberini family; tutor of Francesco and Taddeo and secret waiter of Maffeo (who will be Pope Urban VIII in 1623) later became the secretary of the memorials and the superior for the work on his tomb, commissioned to Bernini since 1627. He was elected cardinal in 1644 becoming himself a collector and patron of artists.
One portrait represents St. John the Baptist, the other St. Jerome: the combination of St. John the Baptist - St. Jerome in Valentin's mind was perhaps not of a devotional character: the soft and almost feminine body of St. John the Baptist is to the old but still vigorous one of St. Jerome, how adolescence is to undone maturity, spring to autumn and - why not? - as the Forerunner is to the compiler of the 'Vulgate'.
The Saint John the Baptist that the artist poses in a declamatory gesture to communicate a feeling of noble grandeur, attenuated by the delicate placing of the other hand on the nape of the lamb, is made with loose brushstrokes and modeled with subtle glazes that give volume to the shapes (we look at the saint's bare knee). It is undoubtedly a poetic painting as denoted by the delicacy of the chromatic accords in the coat and in the complexions and above all in the intense and luminous face. The San Girolamo, set up according to the Caravaggesque tradition, is nevertheless conceived in the light of a more mature classicism which translates into a great composure and solemnity of the Doctor of the Church. It is rendered by the artist with a light pictorial material, spread through glazes that give transparency and relief to the figure silhouetted against the dark background.