The reign (1715–1774) of Louis XV saw an initial return to peace and prosperity under the regency (1715–1723) of Philip II, Duke of Orléans, whose policies were largely continued (1726–1743) by Cardinal Fleury, prime minister in all but name. The exhaustion of Europe after two major wars resulted in a long period of peace, only interrupted by minor conflicts like the War of the Polish Succession from 1733–1735. Large-scale warfare resumed with the War of the Austrian Succession (1740–1748). But alliance with the traditional Habsburg enemy (the "Diplomatic Revolution" of 1756) against the rising power of Britain and Prussia led to costly failure in the Seven Years' War (1756–1763) and the loss of France's North American colonies.