Charles Gonzaga was Duke of Mantua and Duke of Montferrat from 1627 until his death. He was also Charles III Duke of Nevers and Rethel, as well as Prince of Arche and Charleville.

The counts of Nevers were the rulers of the County of Nevers, in France, The territory became a duchy in the peerage of France in 1539 under the dukes of Nevers.