De duodecim abusivis saeculi

De duodecim abusivis saeculi (“On the Twelve Abuses of the World”), also titled simply De duodecim abusivis, is a Hiberno-Latin treatise on social and political morality written by an anonymous Irish author between 630 and 700, or between 630 and 650. During the Middle Ages, the work was very popular throughout Europe.

Origin
In the manuscripts, the work is frequently ascribed to a named author, most commonly Saint Cyprian or Saint Augustine; this led to early editions being published among the works of these authors.

In 1905, however, John Bagnell Bury pointed out that it quoted from the Latin Vulgate, which was incompatible with an attribution to Cyprian or Augustine. He pointed out that the ninth abuse was quoted almost entirely in the Collectio canonum Hibernensis, where it was ascribed to Saint Patrick; and that extracts from the same section were quoted in a letter addressed by Cathwulf, circa A.D. 775, to King Charles the Great, and preserved in a ninth-century manuscript. He concluded that this evidence “proves that the treatise is older than A.D., 700, and strongly suggests that its origin is Irish, that it was ascribed in Ireland to Patrick, and travelled to Gaul under his name.”

In his 1909 edition, Siegmund Hellmann (de) adduced further evidence, establishing it as the work of an anonymous Irish author of the 7th century. Since then, its author is conventionally known as Pseudo-Cyprian.

Twelve abuses


De duodecim abusivis condemns the following twelve abuses:

Influence
The work was very influential, both directly and through the Hibernensis; especially the ninth abuse, the unjust king.

There is some direct evidence for the text's popularity in tenth-century England. Bishop Æthelwold of Winchester is known to have donated a copy to the Peterborough house. Ælfric of Eynsham drew on a version included in Abbo of Fleury's Collectio canonum for his Old English treatise De octo vitiis et de duodecim abusivis gradus, in which the section on the rex iniquus was translated whole.

Hellmann points out the extensive influence of the work upon Carolingian writings, such as the mirrors for princes, and later political literature.

Later, the work was quoted by multiple medieval theologians and scholars such as Vincent of Beauvais and John of Wales. Translations and adaptations in multiple vernacular languages were prepared.