This is a singular work in that it is, possibly, “…the earliest notated manuscript of English provenance for this Feast” (Mathiesen, 1983). The manuscript, written in 1343, comes from a time when the feast was first being accepted throughout England. This codex was produced for the Archbishop of Canterbury, and provides the inquiring researcher a clearer view into the development of the complex history of the Feast as its popularity spread through the Catholic world.
To truly understand the importance of the text, it is first important to understand the history behind the feast of Corpus Christi. The feast had its beginnings with Pope Urban IV, leader of the church from 1261 – 1264, who ordered the feast to be observed on the Thursday following Trinity Sunday. The Pope also requested St. Thomas Aquinas to compose the Office, or song of worship, which many believed to be the most beautiful in the Roman Breviary. The feast became popular and spread fairly quickly, finally being introduced to England from Belgium between 1320 and 1325 (Mershman, 1908).
Not official acknowledged by any English bishops until 1320; it was held in Ipswich, Rochester, and Winchester. However, it was not noted in the edicts of the Benedictine Abbey of St. Augustine, the list of feasts and processions, or the declaration of Archbishop Simon in 1332, which formed forty-one official feast days (Mathiesen, 1983). Thus, since this manuscript was created in 1343, it is especially important because of the information it can provide about the very earliest celebration of the Feast in this region: “Apart from considerations of its primacy, the codex also preserves distinct versions of many of the chants and a distinct version of the Office” (Mathiesen, 1983).
Additionally, 1343 was the year a truce was established, indicating the end of the first phase of the 100 Years’ War. Edward III, who had just returned from his exploits in France, vowed to correct the many ecclesiastical abuses that were happening throughout the Church in England. Many of these grievances were specifically discussed in the Regimen Animarum. In September of the same year, King Edward and Parliament addressed the Pope in Avignon with a letter, calling for sweeping changes to be made in order to tackle the many ecclesiastical abuses. These issues are clear in the codex, as there is a general resistance to the Pope, as well as a detailed list of abuses. Mathiesen concludes, “…the Regimen Animarum clearly anticipate[s] the Reformation and make[s] the treatise an important historical source, transcending its original purpose” (1983).