In spite of the Queen mother’s rage at Richelieu’s actions during the spring campaign, Louis honoured him with the new rank of chief minister of State. This was not too soon as the Duke of Mantua found himself once again under siege by the Emperor Ferdinand of Austria, the Holy Roman Emperor. Ferdinand had defeated the northern Protestants and now swung back to regain lost territory. Again, the Grisons suffered as his army swept across to Mantua and could offer little resistance. Casale was again regained by Spain. Champagne in eastern France was being threatened by Ferdinand’s armies. In spite of misgivings, Richelieu placed Marillac, a suspected enemy and the King’s brother, Gaston in command of the defence of the kingdom.
Richelieu was now at the apex of his power, Louis had granted him the post of Lieutenant-General de la Monts which made him supreme commander and the King’s representative in all political and military matters. He was the man to use those powers brilliantly and decisively. As part of the Treaty of Susa, Savoy was obligated to defend Mantua should she come under attack again. Instead of openly breaking the treaty, he used all his powers to hinder the progress of the French army. At the same time, some things went in France’s favour. Plague, fever and flood forced the Spanish to retire from Mantua while Casale continued to hold. The Pope attempted to bring about peace talks but again, Savoy created endless difficulties about the terms for allowing the French through Savoy to gain Montferrat.
Richelieu waited no longer, he swept his army over the Alps to Susa while it was still under French control and set up his headquarters. Charles Emmanuel, the Duke of Savoy holding the area between the French and Spanish armies, continued to play both sides. While Richelieu set up camp he was plotting with Spain to close the passes behind the French army and delayed supplies purchased by France for Casale. In a moment, Richelieu turned his army not towards Casale to relieve her but straight towards the Savoyards themselves which sent them running back to Turin. The army slogged on through early winter weather, crossing swollen rivers and enduring rain and sleet. Richelieu rode at its head surrounded by guards. The men cursed him as they followed him into Rivoli but were well rewarded by Savoy’s fire and wine.
Knowing that he would be leaving his rear flank open if he proceeded against Spain and Austria, he decided on another decisive move. He would block the gateway passes between Dauphine and Piedmont. France would hold the keys to Italy. In May, Richelieu met Louis at Grenoble where together, they conquered Savoy. The Duke of Savoy later died of despair at the loss of his kingdom. Mantua had been sacked by the Emperor’s troops, it’s treasures and the beautiful Gonzaga palace destroyed.
The King and Richelieu continued sending troops to reinforce Pinerolo. Louis’ Italian armies joined with the French troops but disease weakened them. The Duke of Savoy’s son, married to Madame Christine of France, decided it would be wise to ally with France which allowed peace negotiations to continue . The chief agents in them were who else but Pere Joseph, Richelieu’s old friend and an Italian diplomat who served the Pope, one we would hear about in the future, Gulio Mazarani, a young man destined to succeed the Cardinal.
In late October of 1629, The Austrians and Spaniards withdrew from the war, Mantua was returned to Savoy and Casale was relieved. The Cardinal had triumphed but he must still return to France and the danger that awaited him there.