Age is no guarantee of accuracy.
Quote:The mythology of pre-Christian Ireland did not entirely survive the conversion to Christianity. However, much of it was preserved in medieval Irish literature, though it was shorn of its religious meanings. This literature represents the most extensive and best preserved of all the branches of Celtic mythology. Although many of the manuscripts have not survived and much more material was probably never committed to writing, there is enough remaining to enable the identification of distinct, if overlapping, cycles: the Mythological Cycle, the Ulster Cycle, the Fenian Cycle and the Historical Cycle. There are also a number of extant mythological texts that do not fit into any of the cycles. Additionally, there are a large number of recorded folk tales that, while not strictly mythological, feature personages from one or more of these four cycles.
Quote:The Sources
The three main manuscript sources for Irish mythology are the late 11th/early 12th century Lebor na hUidre which is in the library of the Royal Irish Academy, the early 12th century Book of Leinster in the Library of Trinity College, Dublin, and the Rawlinson manuscript B 502 (Rawl.), housed in the Bodleian Library at Oxford University. Despite the dates of these sources, most of the material they contain predates their composition. The earliest of the prose can be dated on linguistic grounds to the 8th century, and some of the verse may be as old as the 6th century.
Other important sources include a group of four manuscripts originating in the west of Ireland in the late 14th or early 15th century: The Yellow Book of Lecan, The Great Book of Lecan, The Book of Hy Many,[1] and The Book of Ballymote. The first of these contains part of the earliest known version of the Táin Bó Cúailnge ("The Driving-off of Cattle of Cooley") and is housed in Trinity College. The other three are in the Royal Academy. Other 15th-century manuscripts, such as The Book of Fermoy also contain interesting materials, as do such later syncretic works such as Geoffrey Keating's Foras Feasa ar Éirinn (The History of Ireland) (ca. 1640), particularly as these later compilers and writers may have had access to manuscript sources that have since disappeared.
When using these sources, it is, as always, important to question the impact of the circumstances in which they were produced. Most of the manuscripts were created by Christian monks, who may well have been torn between the desire to record their native culture and their religious hostility to pagan beliefs resulting in some of the gods being euhemerised. Many of the later sources may also have formed part of a propaganda effort designed to create a history for the people of Ireland that could bear comparison with the mythological descent of their British invaders from the founders of Rome that was promulgated by Geoffrey of Monmouth and others. There was also a tendency to rework Irish genealogies to fit into the known schema of Greek or Biblical genealogy.
It was once unquestioned that medieval Irish literature preserved truly ancient traditions in a form virtually unchanged through centuries of oral tradition back to the ancient Celts of Europe. Kenneth Jackson famously described the Ulster Cycle as a "window on the Iron Age", and Garret Olmsted has attempted to draw parallels between Táin Bó Cuailnge, the Ulster Cycle epic, and the iconography of the Gundestrup Cauldron. However, this "nativist" position has been challenged by "revisionist" scholars who believe that much of it was created in Christian times in deliberate imitation of the epics of classical literature that came with Latin learning. The revisionists would indicate passages apparently influenced by the Iliad in Táin Bó Cuailnge, and the existence of Togail Troí, an Irish adaptation of Dares Phrygius' De excidio Troiae historia, found in the Book of Leinster, and note that the material culture of the stories is generally closer to the time of the stories' composition than to the distant past. A consensus has emerged which encourages the critical reading of the material.