The Sacramentarium Gelasianum (Gelasian Sacramentary) is one of the first known liturgical books of the western church. It is also called the Sacramentarium Gelasianum vetus (Old Gelasian Sacramentary), since it is one of the sources of the Gelasian Sacramentaries of the 8th century CE. The only surviving manuscript was not the first draft but a copy produced approximately 750 CE probably in the monastery of Chelles, located just east of Paris (Sacramentaries). The manuscript is presently housed in the Va…