Duchy of Mantua
Since 1308, the Duchy of Mantua had been ruled by the House of Gonzaga, who also acquired the Duchy of Montferrat in 1574. Both territories were part of the Holy Roman Empire but were of particular importance to the area known as Lombardy, dominated by the Spanish-governed Duchy of Milan. Control of this region allowed the Habsburgs to threaten France's restive southern provinces of Languedoc and the Dauphiné, as well as protecting the overland supply route known as the Spanish Road.