APA (7th ed.) Citation

Gregory XV, P., & Louis XIII, K. o. F. (1621). A letter vvritten by Gregory the XV. Pope of Rome, to the French King: To our most dearely beloued son health in Iesus Christ, Louis the 13. the most Christian King of France. According to the French coppie printed at Paris. 1621. Printed [by Bernard Alsop] for N[athaniel] B[utter].

Chicago Style (17th ed.) Citation

Gregory XV, Pope, and King of France Louis XIII. A Letter Vvritten by Gregory the XV. Pope of Rome, to the French King: To Our Most Dearely Beloued Son Health in Iesus Christ, Louis the 13. the Most Christian King of France. According to the French Coppie Printed at Paris. 1621. London: Printed [by Bernard Alsop] for N[athaniel] B[utter], 1621.

MLA (9th ed.) Citation

Gregory XV, Pope, and King of France Louis XIII. A Letter Vvritten by Gregory the XV. Pope of Rome, to the French King: To Our Most Dearely Beloued Son Health in Iesus Christ, Louis the 13. the Most Christian King of France. According to the French Coppie Printed at Paris. 1621. Printed [by Bernard Alsop] for N[athaniel] B[utter], 1621.