Today we go in Ireland, along the river Boyne, some 15 kilometres from its mouth. Here the river circles an area some 4 kilometres wide: the Bend of the Boyne. Here, a complex sacred landscape was conceived and built. It is a funerary landscape, a place devoted to the burial and to the cult of the dead, a sort of island of the dead. The archaeological area includes three main passage graves: Newgrange, Knowth and Dowth. These structures are all dated to the end of the fourth millennium BC. We are sure that they were tombs as human remains have been found in the decorated stone basins located in many of the chambers, together with offerings for afterlife, for instance polished stone objects. The perimeter of each of these mounds was enclosed in a kerb, that is, a ring of huge stones. Many of these kerbstones, as well as many stones placed in passages and chambers, are decorated with elaborate, abstract motifs: spirals, lozenges, circles. To interpret such a megalithic art, it is usually supposed that the connection between human and divine in Neolithic religion was mediated by a person who credited himself of special abilities in communicating with “other worlds”: the world of the divine and the world of the dead. Basing on contemporary, ethnographic studies, this figure is usually called a shaman. To make their “travels” more convincing and impressive on the people, shamans make use of drugs, which provoke altered states of consciousness and hallucinations. During these hallucinations, the human brain generates geometric images. When, later, the subjects represent their hallucinations in drawings, the results are very similar to those of megalithic art. So perhaps the carvings of the megalithic graves represent these experiences, which were thought to be a sort of reports about travels in the afterworld. Undoubtedly however, a small part of the abstract decorations hint at relatively familiar astronomical correlates, such as for instance the phases of the Moon, or devices to measure sunshadows. The evidence for an astronomical content is not conclusive, but yet, the presence of astronomy at Newgrange is undeniable. Newgrange has a cardioid shape approximately 80 metres across. The interior chamber is accessed by a straight corridor which starts from the monumental facade, reconstructed using the original, shining blocks of white quartz. During the restoration, Michael O’Kelly discovered a feature which had since remained covered by debris and invisible. He called it a roof box. It is a stone-built box which acts as a narrow window built over the entrance. But why? It was known through folk memory, passed down over the centuries, that the corridor had something to do with the Sun rising at the winter solstice but, because of the upward incline of the passage, the midwinter sunlight could not reach the central chamber, stopping short at some point in the corridor. With the discovery of the roof box the situation changed, since the Sun could enter from the window and therefore from an increased height. And indeed, after O'Kelly had polished the window from millennia of debris, the rising Sun at midwinter reached again the chamber, renovating an appointment fixed 5 000 years ago. As at Stonehenge, also here the winter solstice was probably associated with concepts of renewal and rebirth, and this is the reason why the builders carefully designed this huge tomb in such a way, as to fix this appointment between stars and stones. It can be said that this re-discovery of this forgotten appointment also signs the birth of Archaeaostronomy.
