In 1194 in England, King Richard I established a land tax known as Carucage and was later used by King John and Henry III. Its purpose was to replace the Danegeld, a tax raised to pay to the Viking raiders as tribute to stop them from ravaging a land. The Danegeld had become ever more challenging to maintain as many increasingly abstained from paying. Carucage was levied only six times over the next 30 years after which it was itself replaced by a different taxation based on income and personal property. In medieval England, the royal income was from their estates, from feudal lords, and taxation. This concept derived from the Danegeld and asked all free men to pay. It was always unpopular and was therefore rarely collected. Like the Danegeld, the Carucage was aimed at freemen who had land, not serfs or slaves – those who possessed no land. As such, the amount was based on the size of land owned. The taxable value given to an estate was derived from various methods, mainly by a unit of land known as carucate – an area of land capable of tilling with a plough-team of eight oxen. Taxation methods shifted from land to personal property. It ultimately never raised much as compared to other taxes, but was still instrumental in financing the ransom release of Leopold V, Duke of Austria; the land tax given to Philip II of France; and the military campaigns of Henry III, the nephew of King Richard I. Carucage was an usual, experimental taxation based on land. The chief purpose was to increase royal income at a period when the royal finances were burdened ever further by new and greater demands. It was only levied for specific purposes rather than a tax with regular assessment.