The existence of an 18th-century print after this painting, inscribed with the sitter's name, confirms the cardinal's identity.
Marco Gallo was born in Como. After several postings in the papal civil service he was appointed, in 1659, Bishop of Rimini. He was made a cardinal by Innocent XI in 1681 and died in 1683.
Gaulli's portrait, which shows him with the cardinal's biretta (red hat) and mozzetta (short cape) must date from between 1681 and 1683.