 One final element of Gregory’s stance on modal matters that deserves our attention is the contingency or necessity of the past. The opinio communis maintained that the past is somehow necessary in a strong sense, even though it is not absolutely necessary. It seems that Gregory did not go so far as to say that the past is necessary (beyond the normal necessity ex suppositione), but he does make some sort of modal distinction between the past and the future. Thus we can say that Gregory did not think God can change the past, although there has been some disagreement on this issue (Courtenay 1972–73; Schabel 2000, 271–2). Suffice it to say that the time has come for a long and careful treatment of the modal status of the past in medieval thought, to determine whether any thinker ever really thought the past could be changed. The probable answer is negative.