thumb|alt=A painting of four figures riding atop their horses|Riders of the Sidhe, a 1911 painting of the [[aos sí or Otherworldly people of the mounds, by the artist John Duncan]]
thumb|Cuchulain in Battle by [[Joseph Christian Leyendecker, 1911]]
Irish mythology is the body of myths indigenous to the island of Ireland. It was originally passed down orally in the prehistoric era. in certain scholarly circles, and thus a bona fide goddess, e.g., Macalister's translation of the Lebor Gabala. A Welsh goddess Dôn is mentioned as possibly connected,<!--|ps=Bodb--> but only probably. although some members of the two races have offspring. The Tuath Dé defeat the Fomorians in the Battle of Mag Tuired. This has been likened to other Indo-European myths of a war between gods, such as the Æsir and Vanir in Norse mythology and the Olympians and Titans in Greek mythology. Joseph F. Nagy in 1985 further explored the mythical significance of this boundary in Finn Cycle tales, stressing the idea of liminality, where the border was seen as the threshold between the material world and the Otherworld or "sacred otherness".
One comparison allegorize the Ulster hero Cú Chulainn as a warrior-dog, and Finn as a hunter-wolf This two group categorization is one of continuing debate. Some reservations are expressed as to whether Nagy's idea of "liminal" boundaries presents such a starkly opposite dichotomy. The idea that the fíanna differed from the Ulster heroes were less tied to a homeland had been noticed long before Sjoestedt, but the older characterization of the fíanna as "outcasts" or "mercenaries" were inadequate, as T. G. E. Powell explains it, and Sjoestedt's insight demonstrated the fíanna were still attached to the community and not cast out, but were in voluntary exile, and able to return to the community. Likewise, the warrior woman Liath Luachra trained the hero Fionn mac Cumhaill.
The Fianna warrior bands were thus the outsiders, connected with the wilderness, youth, and liminal states.