On the Body and Blood of the Lord (De corpore et sanguine Domini) - Paschasius Radbertus

One of the earliest complete treatises on the Eucharist, Paschasius Radbertus' De corpore contained twenty-two chapters, each answering a specific question related to the Eucharist, and included references and excerpts from the works of the early church fathers and to scripture. Radbertus (c.785-c.865) was a Carolingian theologian and Benedictine monk at the abbey of Corbie in northern France. Around 833, Radbertus first wrote the De corpore and dedicated it to Warin, his former pupil and fellow monk at Corbie, who had traveled to the newly established abbey of Corvey in Saxony and become its abbot. According to Radbertus' prologue, Warin requested a short work on the Eucharist for his new community on the edge of Christendom. In late 843, shortly after Radbertus became abbot of Corbie, he revised and rededicated the De corpore to Charles the Bald, King of the Franks. This second edition included several miracle stories surrounding the Eucharist that did not appear in the first version, as well as a new dedicatory prologue to the king. Throughout the De corpore, Radbertus argued that the Eucharistic bread and wine were the literal body and blood of Christ and not merely symbols of it. Radbertus opened the entire text with a chapter explicitly about this issue. The De corpore also addresses specific aspects of the celebration of the Mass, including the use of ritual objects, and Old Testament precedents for Christ's suffering.