In Figure 3 4 an attempt has been made to represent the demographic, economic and social developments under consideration in diagrammatic form. The rectangular frame is intended to signify the boundary of the five parishes. Boxes inside this frame are therefore concerned with internal developments, while those outside it represent exterior factors or inputs. A chronology has been indicated in the left-hand margin, with the key population estimates at an appropriate point on the right. As far as possible, boxes have been positioned and scaled in relation to the chronology; but, because of restrictions of layout, and also because many of the developments cannot be precisely dated, this visual chronology should be regarded as no more than approximate.

Boxes 1 and 2 represent what we have called the ecological equilibrium of the mid Tudor period: when a comparatively small population was gaining its livelihood – as had the previous five or six generations – by practising pasture farming, with the main emphasis on stock rearing and beef production. From the 1570s, however, this state of equilibrium is being undermined by a sharp population increase 5, which is due partly to internal demographic pressure 4, and partly to the fact that external demographic pressure is engendering an unprecedentedly high rate of immigration 3.