It was probably the difficulty that had been found in raising men and money to resist the expected Danish invasion of 1084, that led William to order the compilation of the celebrated _Domesday Book_ in 1085. This great statistical account of the condition of England was drawn up by commissioners sent down into every shire to make inquiry into its resources, population, and ownership. Therein was set down the name of every landholder, with the valuation of his manors, and an account of the service and money due from him to the king. It did not give merely a rent-roll of the estates, but a complete enumeration of the population, divided up by status into tenants-in-chief of the crown, sub-tenants who held under these greater landowners, burgesses of towns, free "_sokmen_," villeins, and serfs of lower degrees. Under each manor was given not only the name of its present holder and its actual value, but also a notice of its proprietor in the time of King Edward the Confessor, and of its value at Edward's death. This enables us to form an exact estimate of the change in the ownership of the lands of England brought about by the Conquest. We see that of the great English earls and magnates not a single one survived; all their lands had been confiscated and given away at one time or another. Of the thegns of lower degree some still retained their land, and had become the king's tenants-in-chief; many had sunk into sub-tenants of a Norman baron, instead of holding their estate directly from the crown; but still more had lost their heritage altogether. In some counties, especially in the south-east, where the whole thegnhood had fallen at Hastings, hardly a single English proprietor survived. In others, such for example as Wiltshire or Nottingham, a large proportion of the old owners remained; but, on the whole, we gather that three-quarters of the acreage of England must have changed masters between 1066 and 1085. We discover also that while some parts of England had suffered little in material prosperity from the troublous times of the Conquest, others had been completely ruined. Yorkshire shows the worst record, a result of William's cruel harrying of the land in 1070; manor after manor is recorded as "waste," and the whole county shows a population less by far than that of the small shire of Berks. [Sidenote: =The great Moot of Salisbury.=] Having ascertained by the completion of Domesday Book the exact names, status, and obligations of all the landholders of England, William used his knowledge to bid them all come to the Great Moot of Salisbury in 1086, where every landed proprietor, whether tenant-in-chief or sub-tenant, did personal homage to the king, and swore to follow him in all wars, even against his own feudal superior if need should so arise. [Sidenote: =Death of William.=]