Soon after taking office, he confronted several issues, which included opposing trials by ordeal,[2] and, in 818, writing against Felix of Urgel's Spanish Adoptionist Christology.
Jewish communities living in the Frankish or Carolingian realm had been granted considerable freedoms under Louis the Pious son of Charlemagne, including a prohibition on Christian proselytizing.
Agobard found this last provision particularly galling, and wrote his first anti-Jewish tract on the matter: De Baptismo Judaicorum Mancipiorum (c. 823).
[4] For the rest of the decade, Agobard campaigned against what he saw as the dangerous growth in power and influence of Jews in the kingdom that was contrary to canon law.
[10] Agobard's rhetoric, which included describing Jews as "filii diaboli" ("children of the devil") was indicative of the developing anti-Jewish strain of medieval Christian thought.
A passage in it mentions the popular belief in ships in the clouds whose sailors were thought to take crops damaged by hail or storms to their land of Magonia.
[24] Agobard's complete works can be found in Volume 104 of J.P. Migne's Patrologia Latina, and, in a more recent edition, in Van Acker's Agobardi Lugdunensis Opera Omnia.