Flag of the Margraviate of Mantua (1328–1575) Milan ItalyMade to Order 100% Cotton The Duchy of Mantua (Italian: Ducato di Mantova; Lombard: Ducaa de Mantua) was a duchy in Lombardy, northern Italy. Its first duke was Federico II Gonzaga, member of the House of Gonzaga that ruled Mantua since 1328.[1] In 1531, the duchy also acquired the March of Montferrat, thanks to the marriage between Gonzaga and Margaret Paleologa, Marchioness of Montferrat.[2] Duchy of Mantua Ducato di Mantova (Italian) Ducatus Mantu