The old idea that stone circles were Druidic temples, that human sacrifices were offered on the "altar-stone," and libations of blood poured into the cup-markings, must be given up, along with much of the astronomical lore associated with the circles. Stonehenge dates from the close of the Neolithic Age, and most of the smaller circles belong to the early Bronze Age, and are probably pre-Celtic. In any case they were primarily places of sepulture. As such they would be the scene of ancestor worship, but yet not temples in the strict sense of the word. The larger circles, burial-places of great chiefs or kings, would become central places for the recurring rites of ghost-worship, possibly also rallying places of the tribe on stated occasions. But whether this ghost-worship was ever transmuted into the cult of a god at the circles is uncertain and, indeed, unlikely. The Celts would naturally regard these places as sacred, since the ghosts of the dead, even those of a vanquished people, are always dangerous, and they also took over the myths and legends[961] associated with them, such, e.g., as regarded the stones themselves, or trees growing within the circles, as embodiments of the dead, while they may also have used them as occasional places of secondary interment. Whether they were ever led to copy such circles themselves is uncertain, since their own methods of interment seem to have been different. We have seen that the gods may in some cases have been worshipped at tumuli, and that Lugnasad was, at some centres, connected with commemorative cults at burial-places (mounds, not circles). But the reasons for this are obscure, nor is there any hint that other Celtic festivals were held near burial mounds. Probably such commemorative rites at places of sepulture during Lugnasad were only part of a wider series occurring elsewhere, and we cannot assume from such vague notices that stone circles were Druidic temples where worship of an Oriental nature was carried on. Professor Rh[^y]s is disposed to accept the old idea that Stonehenge was the temple of Apollo in the island of the Hyperboreans, mentioned by Diodorus, where the sun-god was worshipped.[962] But though that temple was circular, it had walls adorned with votive offerings. Nor does the temple unroofed yearly by the Namnite women imply a stone circle, for there is not the slightest particle of evidence that the circles were ever roofed in any way.[963] Stone circles with mystic trees growing in them, one of them with a well by which entrance was gained to Tír fa Tonn, are mentioned in Irish tales. They were connected with magic rites, but are not spoken of as temples.[964] ALTARS.