The Great Heathen Army, also known as the Great Army or the Great Danish Army, is a Viking army originating in Denmark which pillages and conquers much of England in the late 9th century.
Unlike many of the Scandinavian raiding armies of the period, surviving sources give no firm indication of its numbers, but it is clearly among the largest forces of its kind, comprising a number of ships reaching into the hundreds, and many thousands of men.