The sacramentary was a liturgical book used for prayer during the High Middle Ages, containing the prayers, prefaces, and canons for mass. Drogo (801–55), bishop of Metz, son of Charlemagne, and famous patron of his era, had a gorgeous copy of the sacramentary made in Metz around 845–55. The manuscript, which is on vellum, is the work of several artists employed by the imperial court. It is written in a clear Latin script and includes some of the most beautiful fleurons ever produced in Metz. The illumination is made of illustrated initial letters, decorative arcatures, and gilded letters, and is distinguished both by the finesse and dynamism of the characters and by the delicacy of its emerald green, sky blue, violet, and purple colors and its pronounced taste for plant-based ornamentation. The iconography of the illumination is centered on the life of Christ, and corresponds to that of the binding's ivory plates. Executed in the same era and by the same workshop as the manuscript, both the front and back plates are divided into nine platelets sculpted in relief. The platelets illustrate the main sacraments (upper plate) and scenes from the church liturgy (lower plate). The sacramentary would have been used in Metz's Carolingian cathedral, and constitutes a precious record of the liturgical practices of the time and the accoutrements used in the liturgy. In the 16th century, the plates were put back on the manuscript over green-velvet covered boards and embedded in a silver lining adorned with acanthus leaves.