The survival of Irish mythology and folklore owes much to the Romans and the fact that they decided Ireland was too distant a territory to conquer and left the country alone. This allowed the Celts of Ireland to develop a Gaelic society of their own that even with the conversion to Christianity, held a certain autonomy from the rest of Christian Europe. Indeed, though they altered the religious significance of the mythologies, the religious clerics of the Dark Ages and Medieval Period transformed much of Ireland’s ancient oral history into texts such as the Annals of the Four Masters and the Book of Leinster, which are found at Trinity College.
Irish mythology, folk tales and history is separated into four cycles – the Mythological Cycle, the Ulster Cycle, the Fenian Cycle and the Historical Cycle. These cycles define important events in Irish history, from the Invasions of Ireland by the various Celtic tribes, to the division of the country into the five Gaelic provinces of Ulster, Leinster, Meath, Connacht and Munster, which (with the exception of Meath) are still used in the administration of Ireland. Within the early cycles are the stories of legendary heroes such as Cu Chullain and Fionn Mac Cumhaill, while the historical cycle outlines the lineage of the High Kings of Ireland up to Brian Boru in the 11th Century.
As well as illustrating the origins of Irish History many of the legends and folktales have influenced the writings of some of Ireland’s most prominent literary figures such as W.B. Yeats and Seamus Heaney and even today the folktales and legends of old are taught in Ireland’s schools.