Prophesies and Vaticinal literature were important elements in medieval Ireland. Fore-knowledge is claimed in St. Patrick’s Confessions, while Adomnan devotes a third of his Life of Columba to the saint’s prophesies. Prophesy was used to justify political conditions. The tenth-century Tripartite Life of Patrick has the saint predicting Ireland’s political history. Prophesies were a convenient medium for commentary or dissension. The Prophecy of Berchan was begun in the ninth century with verses on the Vikings, and continued in the eleventh century with a critical recitation of Irish and Scots high kings. A contemporary prophesy is attributed to Bec mac De, and it condemns father to son succession in the headship of Armagh. Opinion on important clergy is found in the Prophecy of Bricin, composed around 1000.
Prophesies were also attributed to legendary individuals. An early eighth-century recitation of princes is the Prophecy of Conn of the Hundred Battles. This work was the model for an eleventh-century composition known as the "Phantom’s Frenzy," written by Dub-da-Leithe of Armagh. A phantom and a lady who represents the sovereignty of Ireland tell Conn who will rule Ireland. Conn’s son Art is made the author of a prophesy that foretells his death at the battle of Mag Mucruimhe and the arrival of St. Patrick.
A group of prophesies from the tenth and eleventh centuries has the theme of the Last Days. Works such as the "Fifteen Signs of Doomsday" and the "[Day of] Judgment" describe the end of the world. After the mid-tenth century are prophesies about destruction associated with the feast of John the Baptist. This culminated in a panic throughout Ireland in 1096 when certain chronological conditions, described in the "Second Vision of Adomnan," were believed to herald this disaster.
The twelfth century saw a reaction to prophetic works. The "Vision of Mac Con Glinne" mocks the "Phantom’s Frenzy," and instead of a list of rulers there is a list of delicacies for a feast. Nevertheless, prophetic texts continued to be produced. The "Poem of Prophecies," about the evils of the age, is a continuation of an eleventh-century text. Contemporary is a prophesy attributed to St. Moling, concerned mainly with Leinster affairs.
The Anglo-Norman invasions inspired a new wave of original composition. A prophesy attributed to St. Columba, addressing his friend Baitin, called "Harken O Baitin," places the invaders in the general context of Irish history. Ironically, the Anglo-Normans were enthusiastic students of Irish prophesies, and Gerald Cambrensis’ Conquest of Ireland originally was called the Vatican History. He claims that the adventurer John de Courcy had a volume of Irish prophesies, which he believed had foretold his conquests. In later medieval Ireland prophesy increasingly became subordinated to contemporary affairs. Odes to princes usually claimed that their reigns had been foretold by an ancient prophet. At the end of the Middle Ages, prophesy had become a cliche in Irish society.
