Magonia (mythology)

Magonia is the name of the cloud realm whence felonious aerial sailors were said to have come according to the polemical treatise by Carolingian bishop Agobard of Lyon in 815, where he argues against weather magic. The treatise is titled "De Grandine et Tonitruis" ("On Hail and Thunder").
Description.
The inhabitants of this realm were said to travel the clouds in ships and worked with Frankish "tempestarii" ("tempest-raisers" or weather-magi) to steal grain from the fields during (magically raised) storms.
Document history.
Agobard's works were lost until 1605, when a manuscript was discovered in Lyon and published by Papirius Masson, and again by Baluze in 1666. For later editions see August Potthast, "Bibliotheca Historica Medii Aevi". The life of Agobard in Ebert's "Allgemeine Geschichte der Literatur des Mittelalters im Abendlande" (1880), Band ii., is still the best one to consult. For further indications see A. Molinier, "Sources de l'histoire de France", i. p. 235.
Popular culture.
Magonia is featured in Jacques Vallee's book "Passport to Magonia", which explores the link between modern UFO visitations and reports from antiquity of contact with these "space beings" where he quotes Agobard's description.
Maria Dahvana Headley's young adult novel "Magonia" also references the mythological realm.