Charles Emmanuel I, Duke of Savoy
After the victory of Fontaine-Française (1595), Henry took Jeannin into his council and in 1602 named him intendant of finances. He took part in the principal events of the reign, negotiated the Treaty of Lyon with Charles Emmanuel I, Duke of Savoy, and the defensive alliance between France and the United Netherlands in 1608. As Superintendent of Finances under King Louis XIII, be tried to establish harmony between the king and the Queen Mother, Marie de' Medici.