Banker at Ferrara, Italy, in the eighteenth century. He often transacted business with Pope Clement XIII. and with his successor, Clement XIV. On Feb. 22, 1764, Clement XIII. requested Coen to provide the papal government with as much corn as possible and with 4,000 sacks of Indian wheat, to be shipped either at Ancona or at Civita Vecchia, leaving the price to be settled by him.
Especially intimate were Coen's relations with Pope Clement XIV., whose confidential friend and adviser he became. He consequently shared in the lampoons directed against Clement. During the famine of 1772-73 Coen came to the rescue of the government and furnished it with 5,000 sacks of Indian wheat.
During the French invasion of 1798 Coen was one of the commission of six appointed to sell the property confiscated by the provisional government.