Gaulli’s early artistic training seems to have taken place in Genoa, where he saw the art of Rubens and Van Dyck. He moved to Rome in 1657 where he met the renowned sculptor, architect and painter Bernini, who became his mentor and promoter. Gaulli introduced into his mature works the influence of Carracci and, at the suggestion of Bernini, the great Parmesan Renaissance master of sensual colourism, Correggio. Through Bernini, Gaulli, when only thirty-two years old, gained the most important commission of his time, the vast fresco decoration of the Church of the Gesù, and his work was immediately recognized as one of the outstanding accomplishments of the age.
The composition is innovative: the saint points at the figure of Christ himself in the distance rather than to a lamb symbolizing him. The iconography is that of the Baptist as hermit in the wilderness near Bethany beyond the Jordan River, pointing to the distant figure of Christ as he approached him and observing, “Behold, the Lamb of
God [who takes away the sin of the world!]”
In the late style of Gaulli, the colours become less intense, allowing for subdued and pastel colours to be more predominant reflecting to the developing taste for the proto-Rococo in Rome.