The Nine Years' War (1688–1697), also known as the War of the Grand Alliance or War of the League of Augsburg, was a conflict between France and the Grand Alliance, a coalition including the Holy Roman Empire, the Dutch Republic, England, Spain, and Savoy. While concentrated in Europe, fighting spread to the Americas, India, and West Africa, and it has been called the first ever world war. Related conflicts included the Williamite war in Ireland, and King William's War in North America.

Louis XIV of France emerged from the Franco-Dutch War in 1678 as the most powerful monarch in Europe. Using a combination of aggression, annexation, and quasi-legal means, he then set about extending his gains to strengthen France's frontiers, culminating in the 1683 to 1684 War of the Reunions. The Truce of Ratisbon guaranteed these new borders for twenty years, but concerns among European Protestants over French expansion and anti-Protestant policies led to the creation of the Grand Alliance, headed by William of Orange.

Louis XIV's decision to cross the Rhine in September 1688 was designed to extend his influence and pressure the Holy Roman Empire into accepting his territorial and dynastic claims. However, Leopold I, Holy Roman Emperor and German princes supported the Dutch in opposing French aims, while the November 1688 Glorious Revolution secured English resources and support for the Alliance. Over the next few years, fighting focused around the Spanish Netherlands, the Rhineland, the Duchy of Savoy, and Catalonia. Although the initial military balance favoured France, by 1696 neither side was able to gain a significant advantage, and the main belligerents were financially exhausted, making them keen to negotiate a settlement.