But still, Danelaw lasted until 1066. Nasty fighting.
Actually, the menace was largely controlled in 878 at the battle of Edington. The last Viking King, Eric Blood Axe, was expelled from Northumbria in 954.
1066 was the invasion by the Norman Angevins under William the Conqueror at the battle of Hastings, where King Harold got an arrow in the eye. That established Angevin rule in the UK and French became the lingua Franca until Geffrey Chaucer re-established English again with the writing of his Canterbury Tales written between 1387 and 1400. The Norman Conquest of 1066 was the last successful invasion of the British Isles, largely due to its naval power and superiority. The closest shave was the Spanish Armada of 1588. This was soundly defeated by Sir Francis Drake and Lord Howard. Only one of the Spanish mighty galleons made it back to Spain. The Spaniards suffered enormous loss of life.
Drake was Knighted by Queen Elizabeth I at the naval academy at Greenwich on the Thames just a little down river from London. If any of you visit London, I strongly recommend a boat trip down to Greenwich to the naval college. This is also the site of the old Royal Observatory, where you can walk across the zero meridian. You can see the telescopes of former astronomer royals and time pieces that kept the world's time and the chronometers that allowed for accurate navigation around the world. I took three of my grandchildren there a year ago, and they thought it was the most interesting day of the trip.