Archaeological findings, in conjunction with contemporary quantitative data from manorial records, demonstrate that most of the English population before the onset of the Black Death (1348–1350) suffered from a chronic shortage of protein, calcium, and Vitamin B12 for at least one generation—much longer than the three years of bad harvests and grain famine typically attributed to the Great Famine (1315–1317). The skeletal evidence suggests that after the Great Famine had thinned the population of its frailest individuals, the Great Bovine Pestilence (1319–1320), which caused a prolonged dearth of dairy products, created a generation of people who were less healthy than those who had survived the famine and who therefore were particularly susceptible to the ravages associated with the Black Death.