Charlemagne, anxious to introduce the Roman Rite into his kingdom, wrote to Pope Adrian I between the years 781 and 791 asking him to send him the service-book of the Roman Church. The book sent by the pope is the nucleus of the Gregorian Sacramentary. It was then copied a great number of times, so that there are many versions of it, all containing additions made by the various scribes. The original book sent by Adrian to Charlemagne is easily distinguished from the different editions because the first to supplement Adrian's book from other sources was a conscientious person who carefully noted where his additions begin, adding a note: "So far the preceding book of Sacraments is certainly that edited by the holy Pope Gregory." In the earlier versions we may take the first part, down to this note, as being the book sent by Adrian.