40 Some SACRED GEOMETRY: the Crucuno quadrilateral and the orientation of megaliths

The Crucuno quadrilateral is situated in a field called “parc vein glass” (the field of the blue stone) in Plouharnel, Brittany, France. The rectangle measures 30x40 megalithic yards and its diagonal measures 50. It consists of two Pythagorean triangles of 3-4-5 proportions determined by the diagonal, forming a 3-4 rectangle. This is quite amazing, because it shows that the “Pythagorean” triangle was already known in the Neolithic period.

Another particularity of the 3-4-5 Crucuno rectangle: it is perfectly oriented east-west and its corners point at the sunrise and sunset of the solstices. Theoretically, a 3x4 rectangle should have a latitude of 47°31’ at Crucuno to show the solstice sunrises and sunsets at its corners (taking into account the obliquity of the ecliptic around 1800 BC). The latitude of Crucuno is 47°37’5’’, which is close.

This same orientation principle can be found in cathedrals, churches and chapels until the end of the middle ages. A good example is the Templar chapel in Laon, France, built around 1180:

Most megalithic monuments have a N-E or S-E orientation, which means: the direction of the sunrise on the summer solstice and the winter solstice. The majority is oriented towards the winter solstice, which marks the end of the shortest days, and the returning of light. The orientations aren’t rigid at all. The topographical situation has to be taken into account, like hills obscuring the horizon. And our ancestors weren’t trying to be “scientifically” accurate, it seems to have been a more symbolical expression, an approximation. The figure below shows that many dolmen have a N-E orientation (summer solstice) between 90° and 100°, and that the largest group has a N-S orientation (winter solstice) between 120° and 180°. Nevertheless, some megaliths show an astonishing perfect orientation. Like the chambered mound of Newgrange in Ireland, known for the illumination of its passage and chamber by the winter solstice sun, the sun fertilizing the womb of the earth as it were.

Prehistoric solstice cults were sometimes taken over by the church. An example is the St Peter and St Guidon church in Anderlecht, Brussels. According to tradition, in the second half of the 11th century, a horse ran up against a stone on the top of a hillock. This stone proved to be a dolmen that was surrounded by a hedge, because it couldn’t be moved. The remains are in the crypt of the church. On the winter solstice, a sunbeam falls through the opposite window to lighten the space under the stone. Pilgrims used to crawl under the stone in the direction of the light beam.

Saint Guidon crypt, Brussels

The Crucuno Dolmen, not far from the quadrilateral