In C.1300 around half of all peasant land in England, and half its rural population, were servile. This proportion could not subsequently rise, because the common law presented legal obstacles to any further enserfment of freemen and free tenures. The size of the English population was slashed by around 40% during the first outbreak of the Black Death in 1348–9, and remained stagnant for the next 150 years. Its size is estimated at 2.8 million people in 1377, and slightly lower in the 1520s. Thus the number of serfs fell after 1348–9, and thereafter their proportion within the general population gradually fell until there were hardly any left in the early sixteenth century. Villein tenure, meanwhile, evolved into leasehold and various forms of copyhold. Four main reasons have been advanced to explain the decline of serfdom during the later Middle Ages: manumission; economic pressures; peasant resistance; and migration. Two other associated issues warrant exploration. The first is whether English landlords attempted to impose a ‘second serfdom’ in the second half of the fourteenth century, which in turn shaped the scale and nature of peasant resistance and migration. The second is whether the distribution of the few remaining bondmen in the Tudor period provides any clues to the causes of decline. The purpose of this chapter is to review critically the current state of knowledge on these subjects.