The megalithic tombs of Knowth have revealed another secret, thanks to the intuition of a Canadian cartographer. His discovery that many of the carvings on its walls are of the moon was made without visiting Co Meath.
For decades much of the mystery of Knowth related to the significance of its numerous carvings scattered on its walls; comparable with the most spectacular cave drawings anywhere in the world.
This "distinctive art of spirals, angular designs, lozenges, meanders, circles . . . pocked or incised on the surfaces of their passage, chamber or kerbstones", as described in Reading the Irish Landscape by Frank Mitchell and Michael Ryan.
They, like others, classify it as abstract art that "clearly had a deep symbolic significance which is now lost on us". But Dr Phillip Stooke, a planetary cartographer, of the University of Western Ontario in Canada, has established that many of the carvings are Stone Age maps of the moon.
Moreover, the work of the neolithic farmers at Knowth some 5,200 years ago has rewritten history, as it had been believed that the earliest known moon map was drawn by Leonardo da Vinci in 1505.
Dr Stooke, who regularly works with NASA in charting the planets of outer space, has a particular interest in the history of lunar planetary mapping. He simply refused to accept that da Vinci's 500-year-old map was the earliest.
"I knew there had to be an older map," he told The Irish Times. "It seemed to me, everybody was able to look up and see markings on the moon. So I assumed there must be older pictures."
He spent a great deal of time searching through manuscripts, records and neolithic carvings, with particular attention to circular motifs. It brought him through many ancient civilisations such as the Egyptians, the Greeks, the Romans and the Chinese.
It was the neolithic carvings at Knowth that jumped out at him. Research reports of UCD Department of Archaeology, notably of excavations at Knowth dating from the 1960s, clinched it.
The key characteristic is thick lines corresponding with the vast seas of the moon which approximate to horseshoe shapes (but less a small amount from each end part of the shoe) clearly visible on a full moon.
The process of verification began with his drawing of the moon with the naked eye, "the same view anybody in the ancient world would have". He placed a copy of the stone markings over his sketch of the full moon to show how they match.
Crucial to verification, he said, was the alignment with isolated spots on the edge of the seas. Isolated spots in the drawings correspond exactly. What was etched on the walls of Knowth was "every bit as good as what Leonardo did".
Moreover, he believes other carvings show how the moon moves, suggesting considerable knowledge of the motion of the moon and indicative of very early scientific expertise; not the work of a primitive people. All told, he claimed six carvings support his theory, including one in Baltinglass, Co Wicklow.
One of the most remarkable Knowth finds in his opinion is a carved stone bowl with its lunar insignia. As these carvings do not have a circular outline, he suspects it may have been drawn with chalk or some form of paint which was worn away.
The twin passages at Knowth face due east and west to receive equinoctial sunrises and sunsets. But, according to Dr Stooke, perhaps the very best of the lunar maps is at the end wall of the east-facing package. This has made him speculate that when the full moon rises in that position it shines down the passage and illuminates this picture - "It shines on a map of itself".
As for the moon's relevance for these ancient people, he said he did not know beyond its obvious religious significance. The sun and the moon featured prominently with their worship of the gods, and in informing the passage of time.
Ironically, Dr Stooke's findings were published some time ago in the Journal for the History of Astronomy, but only in recent months has it been attracting attention. This, he said, was probably because of a series of other significant archaeological findings throughout the world which are believed to have connections with the moon.
Meanwhile, the planetary cartographer with a fascination for the moon's place in history hopes to visit Knowth to view its lunar connections and to see if at a certain time a full moon shines on what to him is its most revealing carving.
