Anyone reading the Solemn Prayers of Good Friday in the Roman rite is at once struck by the clear distinction which exists between the biddings and the collects of this ancient intercession both in language and in rhythm, and closer examination shows that whereas the biddings are almost destitute of rhythmic endings, showing only four in the nine biddings (two each in Biddings VI and VII), the collects abound in them, and not one of the nine collects is without at least one. This enables us to conclude that the biddings are earlier than the collects. For it is known that Roman liturgical composition, like the work of the papal chancery, conformed to the principles of the cursus from some time in the fourth century until the middle of the seventh. Presence of rhythmic endings is therefore useless for dating a document within this period, but in the case of writings before or after it, attention to the presence or absence of cursus can give a good indication of date. The cursus became the rule in the papal chancery from the time of Siricius (384-98), and disappeared after St Gregory the Great (604), and in the case of liturgical composition it prevailed roughly from 350 or a little later until about 650. The collects of the three ancient Roman sacramentarles abound in rhythmic endings. Dom Mocquereau collected about 1030 clausulae from the Leonine Sacramentary, of which only ten did not conform to the rules of the cursus. The Gelasian and Gregorian Sacramentarles show a like adherence to this literary principle, and their prayers nearly all date from within the classic period of the cursus, from the fourth to the seventh centuries.