War of the Mantuan Succession
The War of the Mantuan Succession (1628–1631) was a related conflict of the Thirty Years' War, caused by the death in December 1627 of Vincenzo II, last male heir in the direct line of the House of Gonzaga and ruler of the duchies of Mantua and Montferrat. The territories were key to control of the Spanish Road, an overland route that allowed Habsburg Spain to move recruits and supplies from their Italian possessions to their army in Flanders. The result was a proxy war between France, who supported the French-born Duke of Nevers, and Spain, who backed his distant cousin the Duke of Guastalla. 