The meaning formerly given to Tuatha Dé Danann was “the men of science who were gods,” danann being here connected with dán, “knowledge.” But the true meaning is “the tribes or folk of the goddess Danu,” which agrees with the cognates Tuatha or Fir Dea, “tribes or men of the goddess.” The name was given to the group, though Danu had only three sons, Brian, Iuchar, and Iucharbar. Hence the group is also called fir tri ndea, “men of the three gods.” The equivalents in Welsh story of Danu and her folk are Don and her children.
We have seen that though they are described as kings and warriors by the annalists, traces of their divinity appear. In the Cúchulainn cycle they are supernatural beings and sometimes demons, helping or harming men, and in the Fionn cycle all these characteristics are ascribed to them. But the theory which prevailed most is that which connected them with the hills or mounds, the last resting-places of the mighty dead. Some of these bore their names, while other beings were also associated with the mounds (síd) — Fomorians and Milesian chiefs, heroes of the sagas, or those who had actually been buried in them. Legend told how, after the defeat of the gods, the mounds were divided among them, the method of division varying in different versions. In an early version the Tuatha Dé Danann are immortal and the Dagda divides the síd. But in a poem of Flann Manistrech (ob. 1056) they are mortals and die. Now follows a regular chronology giving the dates of their reigns and their deaths, as in the poem of Gilla Coemain (eleventh century). Hence another legend told how, Dagda being dead, Bodb Dearg divided the síd, yet even here Manannan is said to have conferred immortality upon the Tuatha Dé Danann. The old pagan myths had shown that gods might die, while in ritual their representatives were slain, and this may have been the starting-point of the euhemerising process. But the divinity of the Tuatha Dé Danann is still recalled. Eochaid O’Flynn (tenth century), doubtful whether they are men or demons, concludes, “though I have treated of these deities in order, yet have I not adored them.” Even in later times they were still thought of as gods in exile, a view which appears in the romantic tales and sagas existing side by side with the notices of the annalists. They were also regarded as fairy kings and queens, and yet fairies of a different order from those of ordinary tradition. They are “fairies or sprites with corporeal forms, endowed with immortality,” and yet also dei terreni or síde worshipped by the folk before the coming of S. Patrick. Even the saint and several bishops were called by the fair pagan daughters of King Loegaire, fir síde, “men of the síd,” that is, gods. The síd were named after the names of the Tuatha Dé Danann who reigned in them, but the tradition being localised in different places, several mounds were sometimes connected with one god. The síd were marvellous underground palaces, full of strange things, and thither favoured mortals might go for a time or for ever. In this they correspond exactly to the oversea Elysium, the divine land.
But why were the Tuatha Dé Danann associated with the mounds? If fairies or an analogous race of beings were already in pagan times connected with hills or mounds, gods now regarded as fairies would be connected with them. Dr. Joyce and O’Curry think that an older race of aboriginal gods or síd-folk preceded the Tuatha Dea in the mounds. 1 These may have been the Fomorians, the “champions of the síd,” while in Mesca Ulad the Tuatha Dea go to the underground dwellings and speak with the síde already there. We do not know that the fairy creed as such existed in pagan times, but if the síde and the Tuatha Dé Danann were once distinct, they were gradually assimilated. Thus the Dagda is called “king of the síde”; Aed Abrat and his daughters, Fand and Liban, and Labraid, Liban’s husband, are called síde, and Manannan is Fand’s consort. Labraid’s island, like the síd of Mider and the land to which women of the síde invite Connla, differs but little from the usual divine Elysium, while Mider, one of the síde, is associated with the Tuatha Dé Danann. The síde are once said to be female, and are frequently supernatural women who run away or marry mortals. Thus they may be a reminiscence of old Earth goddesses. But they are not exclusively female, since there are kings of the síde, and as the name Fir síde, “men of the síde,” shows, while S. Patrick and his friends were taken for síd-folk.
The formation of the legend was also aided by the old cult of the gods on heights, some of them sepulchral mounds, and now occasionally sites of Christian churches. The Irish god Cenn Cruaich and his Welsh equivalent Penn Cruc, whose name survives in Pennocrucium, have names meaning “chief or head of the mound.” Other mounds or hills had also a sacred character. Hence gods worshipped at mounds, dwelling or revealing themselves there, still lingered in the haunted spots; they became fairies, or were associated with the dead buried in the mounds, as fairies also have been, or were themselves thought to have died and been buried there. The haunting of the mounds by the old gods is seen in a prayer of S. Columba’s, who begs God to dispel “this host (i.e. the old gods) around the cairns that reigneth.” An early MS also tells how the Milesians allotted the underground part of Erin to the Tuatha Dea who now retired within the hills; in other words, they were gods of the hills worshipped by the Milesians on hills. But, as we shall see, the gods dwelt elsewhere than in hills.
Tumuli may already in pagan times have been pointed out as tombs of gods who died in myth or ritual, like the tombs of Zeus in Crete and of Osiris in Egypt. Again, fairies, in some aspects, are ghosts of the dead, and haunt tumuli; hence, when gods became fairies they would do the same. And once they were thought of as dead kings, any notable tumuli would be pointed out as theirs, since it is a law in folk-belief to associate tumuli or other structures not with the dead or with their builders, but with supernatural or mythical or even historical personages. If síde ever meant “ghosts,” it would be easy to call the dead gods by this name, and to connect them with the places of the dead.
Original article: Tuatha Dé Danann