There have been various debates as to its original purpose. Many archaeologists believed that the monument had religious significance of some sort or another, either as a place of worship for a "cult of the dead" or for an astronomically-based faith. O'Kelly believed that the monument had to be seen in relation to the nearby Knowth and Dowth, and that the building of Newgrange "cannot be regarded as other than the expression of some kind of powerful force or motivation, brought to the extremes of aggrandizement in these three monuments, the cathedrals of the megalithic religion." O'Kelly believed that Newgrange, alongside the hundreds of other passage tombs built in Ireland during the Neolithic, showed evidence for a religion that venerated the dead as one of its core principles. He believed that this "cult of the dead" was just one particular form of European Neolithic religion, and that other megalithic monuments displayed evidence for different religious beliefs that were solar-oriented, rather than ancestor-oriented.