A medieval land tax originally raised to pay off raiding Danes and was later used to fund military expenditures. The tribute was first levied in England in 868 and again in 871. Under the leader Aethelred (978-1016) it became a regular tax until it was replaced during the reign of William the Conqueror. The tax rate was two shillings for every "hide" of land which was about 100-120 acres.