Stonehenge is probably the most recognisable and enigmatic stone circle in Britain. The structure has fascinated people for centuries, and there are many theories as to what purpose it was put to by ancient man. Stonehenge has suffered over the years from trophy hunters, and the wear and tear of many visitors. The structure is now surrounded by a fence, which although not aesthetically pleasing is helping to preserve the monument from erosion.
Archaeologists have agreed that Stonehenge was built in four distinct phases: The first phase began around 3200BC, and consisted of the henge earthwork enclosing a wooden building, which according to Aubrey Burl may have been a charnel house. An outlying stone, the heel stone was also set in place. Around 2400BC 56 pits known as the Aubrey holes after John Aubrey, were dug around the inside of the ditch. Their purpose is unclear but finds of human bones and stone mace heads suggest ritual offerings.
The second phase began around 2200BC, blue dolerite stones with their origin in the Prescilly mountains in Wales, were erected in two concentric circles. An earthen avenue was also created. It is not clear whether the Welsh stones were transported from Wales, or were already in the local area due to the movements of glaciation.
The third phase began around 2000BC, first the blue stones were removed, and the large sarcen blocks erected in the pattern still visible today. The sarcen stones vary in weight from twenty to fifty tonnes, and were quarried and transported from the Marlborough downs eighteen miles away. They were smoothed and finished to precision with stone hand tools, and locked together with mortis and tennon joints. The upper hanging stones in the trilithons are a ball and joint affair. The balls are clearly visible on the taller stones, in the places where the lintels have fallen over the centuries.
The fourth phase began around 1600BC, when the blue stones were re-erected from an unknown storage place to the centre of the great horseshoe.
Stones in the four directions were carved with axe heads and depictions of other weapons, and the stone known as the altar stone was also erected in the centre of the circle, it may have once stood upright.
The stones have inspired many legends and folklore over the centuries. Much of the folklore seems to try and explain the origin of the circle structure as the work of giants, gods or wizards. It was probably easier to accept this than to believe that a past culture could have better technology.
During the Middle Ages Geoffrey of Monmouth, whose colourful writing have had great influence on British mythology, wrote that the stones were originally brought from Africa to Ireland by a race of giants. They were then transported across the sea by the magic of Merlin during the beginning of the Dark Ages on the request of Ambrosius Aurelianus, who was king of the Britons at the time. They were needed as a monument to the treachery of Hengist, a Saxon leader who killed Prince Vortigern.
The heel stone is said to have been thrown by the Devil at a monk who was spying on him between the stones. The stone pinned the unfortunate clergyman to the ground by his heel.
Other folklore suggests that the stones are uncountable, a baker tried to count them by placing a loaf of bread on each stone. He came up with a number but then made the mistake of going through the whole process again, and could never get the sets of numbers to tally.
Stonehenge has stimulated a great deal of debate over the years, from experts and laymen alike. The first account that the stones may have been aligned to key dates was by William Stukeley, who noted that the axis of the earthen avenue aligns to where the sun rises on the longest day.
In the 1960s an astrophysicist called Gerald Hawkins studied Stonehenge alignments by computer, and concluded that the Trilithons framed key dates in the megalithic calendar. Although the alignments are not razor sharp in accuracy, they are accurate enough to have been used by megalithic man for ceremonial and astronomical purposes.
The cycle of the moon is over a 18.61 year cycle, and the observation of the sky must have been over a prolonged period of time to incorporate the correct alignments.