The most important of the many causes which were at work to undermine the manorial system in the fourteenth century is, therefore, plain. The productivity of the soil had declined to a point where villain holdings would no longer support the families which cultivated them and where demesne land was sometimes not worth cultivation even by serf labor. Under these conditions, the very basis of the manor was destroyed. The poverty of the peasants, the difficulty with which tenants could be found for vacant holdings, even though the greatest pressure was brought to bear upon eligible villains, and even though the servile burdens were considerably reduced, and the frequency with which these serfs preferred the uncertainty and risk of deserting to the certain destitution and misery of land-holding, are facts which are intimately connected, and which are all due to the same cause. It had been impossible to maintain the productive capacity of the land at a level high enough to provide a living for the tillers of the soil. Footnotes: [39] E. J. Russell, _The Fertility of the Soil_, Cambridge, 1913, pp. 43-46. [40] _Ibid._, pp. 48-52. [41] _Political Science Quarterly_, vol. xxviii, p. 394. [42] _Ibid._, p. 393. [43] Levett and Ballard, _The Black Death_, p. 216. [44] _Walter of Henley's Husbandry, together with an Anonymous Husbandry, etc._, ed. by Elizabeth Lamond (London, 1890), pp. 19, 71. [45] Curtler, _Short History of English Agriculture_, p. 33. [46] Davenport, _Econ. Dev. of a Norfolk Manor_ (Cambridge, 1906), p. 30. [47] Rogers, _History of Agriculture, etc._, vol. i, pp. 38-44. [48] Cullum, _Hawsted_, pp. 215-218.