The Nine Years' War – often called the War of the Grand Alliance or the War of the League of Augsburg – is a major war of the late 17th century fought primarily on mainland Europe but also encompasses theaters in Ireland and North America.

In Ireland it is often called the Williamite War, and in North America is commonly known as King William's War.

Older texts may even refer to the Nine Years’ War as the War of the Palatine Succession, or the War of the English Succession.King Louis XIV of France had emerged from the Franco-Dutch War in 1678 as the most powerful monarch in Western Europe, but although he had expanded his realm the ‘Sun King’ remains unsatisfied.

Using a combination of aggression, annexation, and quasi-legal means Louis and his ministers immediately set about consolidating and extending his gains in order to stabilize and strengthen his frontiers.

The War of the Reunions (1683–84) had secured Louis further territory, but the King’s revocation of the Edict of Nantes in 1685 had begun a deterioration of French military and political dominance in Europe.

Louis’ belligerence eventually leads to the formation of a European-wide coalition, the Grand Alliance, determined on curtailing French ambition.

The Alliance is led principally by the Anglo-Dutch Stadtholder-King William III, the Holy Roman Emperor Leopold I, King Charles II of Spain, and Victor Amadeus, Duke of Savoy.The war is dominated by siege operations, notably at Mons, Namur, Charleroi and Barcelona; open battles such as Fleurus and Marsaglia are less common.

These engagements generally favor Louis’ armies, but by 1696 France is in a grip of an economic crisis.

The Maritime Powers (England and the Dutch Republic) are also financially exhausted, and when Savoy defects from the alliance in 1696, all parties are keen for a negotiated settlement.

The signing of the Treaty of Ryswick in September 1697 brings an end to the Nine Years’ War, but with the imminent death of the childless and infirm King Charles II, a new conflict over the inheritance of the Spanish Empire will soon embroil France and the Grand Alliance in another major conflict – the War of the Spanish Succession.