Which 1626 battle was a major victory for Tilly over Christian IV of Denmark?

The 1626 battle that gave Tilly a major victory over Christian IV of Denmark was the Battle of Lutter. Fought on 27 August 1626 at Lutter am Barenberge in Lower Saxony, it pitted Christian's Danish-German army against forces led by Johann Tserclaes, Count of Tilly, commander of the Catholic League.

Christian had entered the Thirty Years' War to defend Protestant interests and expand Danish influence in northern Germany. His campaign was weakened by poor weather, supply problems, failed allied operations, and the defeat of Ernst von Mansfeld at the Battle of Dessau Bridge earlier in 1626. Tilly, meanwhile, had received Imperial reinforcements under Wallenstein.

Christian's army was forced into retreat but made a stand at Lutter. Tilly's artillery and coordinated attacks broke the Danish formations, while Christian escaped with cavalry charges after suffering heavy losses. The Danes lost thousands of men, their artillery, and much of their baggage. The defeat effectively ended Christian's hopes of expanding Danish possessions in the Empire, although the war continued until the Treaty of Lübeck in 1629.

A common mix-up is with the Battle of Wittstock, a 1636 Swedish victory, or Rocroi, a 1643 French victory. Neither involved Tilly's decisive defeat of Christian IV.