The people who are studied in these pages lived in six parishes, some with subordinate country chapels: St Oswald's with its three chapels at St Margaret's in the city, Croxdale (St Bartholomew) and Witton Gilbert, St Giles, St Nicholas, Sts Mary the Less and the Bow and St Mary Magdalen.

The size of the population of later medieval Durham is of course unknown to us but some estimate of it in 1548 comes from the returns of the parishes made to the royal surveyors of chantries and such institutions. These were of ‘houseling people’ or those over the age of about 12 years who would be required by church law to go to confession and receive communion at Easter time. One would therefore have to add a multiplier to achieve a total population figure from these, allowing for under-age children. The numbers are St Margaret, 547, St Oswald, 680, St Nicholas, 720, the North Bailey, 240, and St Giles, 420. These figures may have been based on the number of communion hosts which the churches accounted for at Easter, which were often found enumerated in the procurators' accounts for St Oswald's and St Margaret's. The numbers were probably rising by 1548. In 1447–8, 800 hosts were bought for the parishioners of St Oswald's and Croxdale for the Easter communion. In 1467–8 the numbers for St Oswald's were 500, rising to 600 in 1479–80.