From the idea that the sun suffered from his enemies on this day grew the association of Samhain with death.
"The melancholy days are come, the saddest of the year,
Of wailing winds, and naked woods, and meadows brown and sere.
Heaped in the hollows of the grove, the wither'd leaves lie dead;
They rustle to the eddying gust, and to the rabbit's tread.
The robin and the wren are flown, and from the shrub the jay
And from the wood-top calls the crow, through all the gloomy day.
"The wind-flower and the violet, they perished long ago,
And the wild rose and the orchis died amid the summer glow:
But on the hill the golden-rod, and the aster in the wood,
And the yellow sun-flower by the brook in autumn beauty stood,
Till fell the frost from the cold clear heaven, as falls the plague on men,
And the brightness of their smile was gone from upland, glade, and glen."
Bryant: Death of the Flowers.
In the same state as those who are dead, are those who have never lived, dwelling right in the world, but invisible to most mortals at most times. Seers could see them at any time, and if very many were abroad at once others might get a chance to watch them too.
"There is a world in which we dwell,
And yet a world invisible.
And do not think that naught can be
Save only what with eyes ye see:
I tell ye that, this very hour,
Had but your sight a spirit's power,
Ye would be looking, eye to eye,
At a terrific company."
Coxe: Hallowe'en.
These supernatural spirits ruled the dead. There were two classes: the Tuatha De Danann, "the people of the goddess Danu," gods of light and life; and spirits of darkness and evil. The Tuatha had their chief seat on the Isle of Man, in the middle of the Irish Sea, and brought under their power the islands about them. On a Midsummer Day they vanquished the Fir Bolgs and gained most of Ireland, by the battle of Moytura.
A long time afterwards—perhaps 1000 b. c.—the Fomor, sea-demons, after destroying nearly all their enemies by plagues, exacted from those remaining, as tribute, "a third part of their corn, a third part of their milk, and a third part of their children." This tax was paid on Samhain. It was on the week before Samhain that the Fomor landed upon Ireland. On the eve of Samhain the gods met them in the second battle of Moytura, and they were driven back into the ocean.
As Tigernmas, a mythical king of Ireland, was sacrificing "the firstlings of every issue, and the scions of every clan" to Crom Croich, the king idol, and lay prostrate before the image, he and three-fourths of his men mysteriously disappeared.