The final, or French, period of the Thirty Years' War lasted from 1635 to 1648--almost as long as the other three periods put together. Richelieu entered the war not only to humble the Austrian Habsburgs and, if possible, to wrest the valuable Rhenish province of Alsace from the Holy Roman Empire, but also to strike telling blows at the Continental supremacy of the Spanish Habsburgs, who, since 1632, had been actively helping their German kinsmen. The Spanish king, it will be remembered, still held the Belgian Netherlands, on the northern frontier of France, and Franche Comté on the east, while oft-contested Milan in northern Italy was a Spanish dependency. France was almost surrounded by Spanish possessions, and Richelieu naturally declared war against Spain as against the emperor. The wily French cardinal could count upon the Swedes and many of the German Protestants to keep the Austrian Habsburgs busily engaged and upon the assistance of the Dutch in humbling the Spaniard, for Spain had not yet formally recognized the independence of the Dutch Netherlands. Inasmuch as England was chiefly concerned with troublesome internal affairs, the enemies of France could hardly expect aid from across the Channel. [Sidenote: Condé and Turenne] At first, the French suffered a series of military reverses, due in large part to unpreparedness, incompetent commanders, and ill- disciplined troops. At one time it looked as if the Spaniards might capture Paris. But with unflagging zeal and patriotic devotion, Richelieu pressed on the war. He raised armies, drilled them, and dispatched them into the Netherlands, into Alsace, into Franche Comté, into northern Italy, and into Roussillon. He stirred up the Portuguese to revolt and recover their independence (1640). And Mazarin, who succeeded him in 1642, preserved his foreign policy intact. Young and brilliant generals now appeared at the head of the French forces, among whom were the dashing Prince of Condé (1621-1686), and the master strategist Turenne (1611-1675), the greatest soldier of his day. The former's victory of Rocroi (1643) dated the commencement of the supremacy of France in war, a supremacy which was retained for a century. [Sidenote: Peace of Westphalia (1648)] Finally, Turenne's masterly maneuvering against the Spaniards and his forcible detachment of Maximilian of Bavaria from the imperial alliance broke down effective opposition and ended the Thirty Years' War in the Germanies. The various treaties which were signed in 1648 constituted the peace of Westphalia.