Welsh tradition, and bards such as Aneirin (the reputed author of Y Gododdin) are thought to have been court poets in the Hen Ogledd. Nature of the sources A listing of passages from the literary and historical sources, particularly relevant to the Hen Ogledd, can be found in Sir Edward Anwyl's article Wales and the Britons of the North. A somewhat dated introduction to the study of old Welsh poetry can be found in his 1904 article Prolegomena to the Study of Old Welsh Poetry. Literary sources The bardic poetry attributed to Taliesin, Aneirin, and Llywarch Hen. The genealogical tracts of the Harleian genealogies, the Bonedd Gwŷr y Gogledd, and the genealogies of Jesus College MS 20. The Triads of the Island of Britain (note that most of the triads published in the notorious third volume of The Myvyrian Archaiology of Wales are known to be the forgeries of Iolo Morganwg, and are not considered valid sources of historical information). The standard scholarly edition is Trioedd Ynys Prydein by Rachel Bromwich. The other elegies () and songs of praise (), as well as certain mythological stories, that have been preserved. Stories praising a patron and the construction of flattering genealogies are neither unbiased nor reliable sources of historically accurate information. However, while they may exaggerate and make apocryphal assertions, they do not falsify or change the historical facts that were known to the bards' listeners, as that would bring ridicule and disrepute to both the bards and their patrons. In addition, the existence of stories of defeat and tragedy, as well as stories of victory, lends additional credibility to their value as sources of history. Within that context, the stories contain useful information, much of it incidental, about an era of British history where very little is reliably known. Historical sources The Historia Brittonum attributed to Nennius The Annales Cambriae The Anglo-Saxon Chronicle The Ecclesiastical History of the English People by Bede The Annals of Tigernach These sources are not without deficiencies. Both the authors and their later transcribers sometimes displayed a partisanship that promoted their own interests, portraying their own agendas in a positive light, always on the side of justice and moral rectitude. Facts in opposition to those agendas are sometimes omitted, and apocryphal entries are sometimes added. While Bede was a Northumbrian partisan and spoke with prejudice against the native Britons, his Ecclesiastical History of the English