Today is the Spring Equinox, a date that people have been marking for at least five or six millennia, and the most spectacular manifestation of which was revealed when, following our excavations at La Hougue Bie, Jersey (1991-1995), the concrete access tunnel that had been built in the 1920's was demolished, allowing the suns rays once again to shine into the passage as its builders had intended. It was my colleague, Olga Finch, with her partner, Peter Bohea, who were the first to witness this in more than four thousand years.
Most archaeological excavations seem to leave at least some enduring mysteries in their wake, but the one that troubles me here relates not to the orientation of the megalithic structure itself, built by people whose names we will never know, but to a much more recent structure on top of the mound built by a man whose name we do know, the 16th Century Catholic priest, Richard Mabon.
The general sequence at La Hougue Bie is detailed on my website: http://www.mark-patton.co.uk/. The megalithic monument was deliberately sealed and abandoned, as were most of the larger European passage graves, in the 3rd Millennium BC. Although the mound would always have been a conspicuous feature of the landscape, there is no evidence for any further activity on the site until the 12th Century AD, when a chapel was built on the summit, dedicated to Notre Dame de la Clarté (Our Lady of Light). Although some authors have commented on the similar proportions of the chapel and the chamber of the underlying passage grave, the two structures are not on the same alignment and the dimensions of the chapel are largely determined by the available space on the summit of the mound (which seems not to have been levelled to any significant extent by the Medieval builders, to judge from the material found in the various rubble layers that overlay the prehistoric structures on the flanks of the mound). There is no evidence, therefore, to suggest that the builders of the chapel had any direct knowledge of the structure underneath.
At some time between 1515 and 1520, Richard Mabon, who had been Dean of the island since 1509, returned from a pilgrimage to the Holy Land. The chapel at La Hougue Bie had, by this stage, fallen into disrepair, and Mabon resolved to restore it. In fact, he divided the existing chapel into two with an internal wall, and removed most of the eastern wall, inserting a circular oratory, styled on the Holy Sepulchre in Jerusalem. It would later be claimed that he contrived dubious miracles here (candles that seemed to float in mid-air and a statue of the Virgin who raised her hand in benediction) in order to extract money from the credulous, but this may simply be propaganda put about as the Protestant Reformation swept over the island in the 1550's.
Of particular interest here is the small window that Mabon included as part of his oratory since, unlike the chapel itself, this is on the same alignment as the underlying megalithic passage. The crucial question is this: can we believe this alignment to be coincidental, or must we assume that Mabon somehow had knowledge of the megalithic structure? When I discussed this question some years ago with my colleague, the medievalist, Dr Warwick Rodwell, I was of the former opinion and he was of the latter. We agreed to differ, but now I am less sure.
It is possible that the contours of the mound as it existed in the 16th Century gave a clue as to the position of the passage entrance. It is also possible that Mabon, aware of the legend which held the mound to be the burial place of a murdered knight, conducted a small excavation of his own. Our excavations found no evidence for this, but any such evidence could have been destroyed by the excavation trench of the 1920's, which led to the discovery of the passage grave. The megalithic chamber of the passage grave showed no convincing evidence of having been disturbed since prehistory, but it is not necessary to assume that Mabon actually reached the chamber. The excavators of the 1920's found their way along the passage blocked by two broken capstones. We don't know when this damage occured, but if Mabon encountered it he may have been forced to abandon his quest. He may, nonetheless, have aligned his window on what he assumed to be the passage leading to the grave beneath the chapel.
It is hardly likely that Mabon independently decided to align his window towards the equinox. Apart from anything else, it is on the wrong alignment, given its elevation. In any case, the date would have had no real significance for him, his construction pre-dating by some decades the debates within the church that led, in 1582, to the adoption of the Gregorian Calendar.
The alignment could, of course, have been pure coincidence but, with each year that passes, this seems less likely to me.