A Short History of the Middle Ages Fourth Edition

Plate 5.8: Carthusian Diurnal from Lyon (12th cent.). A Diurnal contains daytime monastic chants. On this
page, the scribe has indicated (just beneath each yellow line) the placement of the B natural. Although (or
perhaps because) Carthusian monks rarely came together to pray, they, like other sorts of monks, wanted
clear guidance for their chants.