 But the evidence in all these cases only goes to show that the practice was then being introduced of exposing the Blessed Sacrament with solemnity on occasions of great public calamity or peril, and that for such expositions the period of forty hours was generally selected.In past centuries, especially in the late Middle Ages, the devotion was practiced during times of crisis.Bishops frequently ordered exposition of the Sacrament for “serious and general need.” The faithful would come in shifts before the Sacrament seeking God's intercession during events threatening the local community, such as war, epidemics, drought or famine.