The Battle of Ramillies (pronounced ) was a major engagement of the War of the Spanish Succession fought on 23 May 1706. The encounter was a resounding success for the allied forces of England, the Dutch Republic, and Denmark; but the battle had followed a year of indecisive campaigning in 1705 where Allied over-confidence after their success at the Battle of Blenheim had resulted in an abortive campaign along the Moselle, forcing the Duke of Marlborough to abandon his plans for a push into France. Yet despite the Allies" inability to achieve a decisive victory, Louis XIV was eager for peace; but he wanted it on reasonable terms. Therefore, rather than standing on the defensive, French armies on all fronts swung over to the offensive.

The year 1706 had begun well for Louis XIV"s generals, who had gained early success in Italy and in Alsace, where Marshal Villars had forced the Margrave of Baden to retreat across the Rhine. Louis now pressed Marshal Villeroi to seek out Marlborough and bring the Allies to battle in the Spanish Netherlands. Accordingly, the French Marshal set off from Louvain at the head of 60,000 men, and provocatively marched towards Léau. Marlborough, also determined to fight a major engagement, assembled his forces – some 62,000 men – near Maastricht, before advancing towards the Mehaigne river and the plain of Ramillies. However, the French had anticipated the Allies, and Marlborough"s advance party found the location already occupied. Nevertheless, the Duke decided to attack at once.

In less than four hours, Villeroi"s army was utterly defeated. Marlborough"s subtle moves and changes in emphasis during the battle – something the French and Bavarian commanders failed to realise until it was too late – caught his foe in a tactical vice. The Franco-Bavarian army broke and ran en masse, suffering over 20,000 casualties. With Prince Eugène"s subsequent success at Turin in northern Italy, the Allies had imposed the greatest loss of territory and resources that Louis XIV would suffer during the war. Town after town – including Brussels, Bruges and Antwerp – fell to Marlborough"s forces and by the end of the campaign, the Franco-Spanish army had been driven from most of the Spanish Netherlands. The year 1706 had indeed proved to be the Allies" annus mirabilis.