It was shown in Chapter 7 that infant deaths made a major contribution to the overall mortality at Penrith. It is possible to determine infant mortality in the 16th and 17th centuries only by family reconstitution techniques, and such studies are necessarily confined to relatively small populations. Lifetable burial series for the community at Penrith in successive cohorts are shown in Table 7.1 and it can be seen that infant mortality declined progressively in the 17th and 18th centuries, but child (age 1 to 14 years) mortality correspondingly increased. This was because of the spread of a lethal, infectious disease, smallpox, as suggested in section 7.3.2, and we show in this chapter that it was a major factor in determining mortality patterns and the demography of England in the 17th, 18th and 19th centuries.

There are reasons to believe that smallpox as a human disease was of great antiquity; lesions on the mummified face of Rameses V, dated 1160 BC, suggest that he died of smallpox (Dixon, 1962) and the disease is first clearly described by the Persian physician, Rhazes, in about AD 900 (Kahn, 1963). It was spread through Europe by the Saracen invaders and by the returning Crusaders. The Spaniards took smallpox with them to the West Indies in 1507 and to Mexico in 1520, decimating the Indian population (Cliff & Haggett, 1988).

Smallpox was apparently rarely lethal in England until the 1630s (Appleby, 1981), and many accounts suggest that a particularly virulent strain began to afflict people at that time (Corfield, 1987) with a gradual but significant increase in the case fatality rate (Razzell, 1977).