Otia Imperialia

Also known as the "Book of Marvels", it primarily concerns the three fields of history, geography, and physics, but its credibility has been questioned by numerous scholars including philosopher Gottfried Leibniz, who was alerted to the fact that it contains many mythical stories.

[5] S. E. Banks and James W. Binns, editors and translators of what is considered to be the definitive version of the Otia, suggest that the work was completed in the last years of Otto IV's life, saying "it seems most likely [...] that the work was sent to Otto sometime in 1215", due to the inclusion of the death of William the Lion, King of Scotland, which took place in 1214, and the fact that King John was still living while it was written; John died in 1216.

[6][full citation needed] He travelled widely, studied and taught canon law at Bologna, was in Venice in 1177, and at the reconciliation of Pope Alexander III and Frederick Barbarossa.

Like Honorius of Autun’s Imago mundi and Vincent of Beauvais’s Speculum naturale, the Otia imperialia contains fables attributed to Pliny the Elder and Solinus,[12] as well as other tales and folk beliefs, including the Fairy Horn, a Gloucester variety of the widespread fairy cup legend; the supernatural powers of Virgil;[13] the folk belief that a priest's cloak could be viewed as an element pitting good Christians against the Devil;[14] and the first recorded instance of the Wandlebury Legend, which Gervase summarizes as follows:In England, on the borders of the diocese of Ely, there is a town called Cantabrica, just outside which is a place known as Wandlebria, from the fact that the Wandeli, when ravaging Britain and savagely putting to death the Christians, placed their camp there.

[15] One describes the “neptunes” or “portunes,” diminutive humanoids found in France and England, which help peasants finish their domestic chores, but also delight in leading English travellers’ horses into mud.

Another is the Grant, a creature of English legend which resembles “a yearling colt, prancing on its hind-legs” and which runs through towns to warn of impending fire.

Gottfried Leibniz, who edited parts of it,[18] called it a "bagful of foolish old woman's tales",[1] while its modern Oxford University Press editors less dismissively report "a wealth of accounts of folklore and popular belief".