The Middle Ages might have had no quartz watches, no satellite time signals, no laws of entropy, no relativistic electrodynamics, but they were familiar enough with the numerous shades of meaning that inform our own daily uses of the word ‘time’ and its cognates, if we allow for slight differences of vocabulary and nuance. ‘Time when’ and ‘time how long’, both of them judged on scales of minutes, hours, years, centuries, were distinguished then more or less as now. The finiteness of human life was – then as now – what led ordinary people to wax philosophical on the subject of long periods of time duration. ‘The life so short, The task so hard to learn.’ It is a short step from thinking about the finiteness of one human life to the finiteness of mankind and the created world as a whole. In the same way our own experience is carved up into intervals of day and night in the way it has always been, give or take a little tampering at the edges of night, using artificial light. The length of a day remains the same. When we come to smaller intervals of time, time as experienced depends largely on what there is to fill it, and it is here that we differ most from those in the monastery. Measuring the hour, rather than the millisecond, was nevertheless something they wanted to do.

Here, then, are the three rough divisions into which I have divided this chapter: time in the longest intervals conceivable, time taken day by day throughout the year, and the hours into which the day is conveniently subdivided.

While the length of human life sets us thinking about the longest intervals of time, that does not mean that we all draw similar conclusions. Eschatology is the hidden variable. Attitudes to the ‘four last things’ – death, judgement, heaven, and hell – radically affected the medieval Christian outlook on time on the largest scale. While a few daring individuals played with Aristotelian fire, and considered the possibility that the world had no beginning in time, for most Christians the Old Testament account of creation meant that the world had existed for a few thousand years at most.