Peace at last (for the time being)! On August 5, 910, the last major army sent by the Danes to raid England was defeated at the Battle of Tettenhall, near modern-day Wolverhampton.
Frequent Danish raids over the preceding centuries had placed significant parts of Northeast England under their control. Although they attempted to attack areas in central England, they were resisted by Alfred the Great and his son, Edward of Wessex, who eventually got bold and attacked the Danes in their own territories, aided by his allies, the Mercians. In 909, Edward and the Mercians attacked the Kingdom of Lindsay and captured the relics of Saint Oswald of Northumbria.
This five-week raid seriously pissed off the Vikings, who assembled a fleet and dispatched an army straight into the heart of Mercia. They ravaged and pillaged their way through the area for a while, and then realized that it might be unwise to remain in enemy territory for long. They thought they had time to head back to Northumbria because Edward was supposed to be massing a fleet of ships in Kent.
Surprise! Edward was not in Kent, but meeting with his Mercian allies. Their army quickly surrounded the raiders, who tried to flee north and found the route to the sea blocked. With no way to escape, they had no choice but to engage in a battle. Little is known of the battle itself, but we do know the Vikings got their asses kicked. Thousands of them, including the two kings leading the raid, were killed.
The Danes were duly humbled, and the allies were gaining in strength. Soon, England was united under one monarch, and the Danish expansion in England was stopped permanently, although they continued to live in the northern part of the country.