More than nine hundred stone rings exist in the British Isles, and scholars estimate that twice that number may originally have been built. Scholars usually classify these types of megalithic structures as rings rather than circles, because the rough proportions for the different shapes are 2/3 true circles, 1/6 flattened circles, 1/9 ellipses, and 1/18 eggs. Stonehenge, however, is roughly circular. It is difficult to precisely date the stone rings because of the scarcity of datable remains associated with them, but it is known that they were constructed during the Neolithic period. In southern England the Neolithic period dates from the development of the first farming communities around 4000 BC to the development of bronze technology around 2000 BC, when the construction of the megalithic monuments was mostly over. Because of the limited nature of the archaeological record at the stone rings, attempts to explain the functions of the structures are often interpretive. Interpretations of the stone rings made in previous centuries tended to reflect the cultural biases of their times and were sometimes wildly imaginative. Only in the past few decades have truly comprehensive examinations of Stonehenge been conducted by archaeoastronomers such as John Michell, Robin Heath and John North. It is interesting to note that more than 40,000 megalithic sites have survived in the British Isles, this number exceeding the number of modern towns and villages, and yet only a small percentage of these have been thoroughly studied.

In the seventeenth century, well before the development of archaeological dating methods and accurate historical research, the antiquarian John Aubrey surmised that Stonehenge and other megalithic structures were constructed by the Druids. While this idea (and a collection of related fanciful notions) has become an unquestioned belief of popular culture from the seventeenth century to the present age, the Druids had nothing to do with the construction of the stone rings. The Celtic society, in which the Druid priesthood functioned, came into existence in Britain only after 300 BC; more than 1500 years after the last stone rings were constructed. Furthermore, little evidence suggests that the Druids, upon finding the stone rings positioned across the countryside, used them for ritual purposes. Druids are known to have conducted their ritual activities mostly in sacred forest groves. Therefore, a Druidic connection, in a construction sense, with the stone rings is inaccurate. Other seventeenth- and eighteenth-century visitors to the stone rings suggested that these monuments were constructed by the Romans, but this idea is even more lacking in historical possibility than the Druid theory because the Romans did not enter the British Isles until 43 AD, nearly 2000 years after the construction of the stone rings.

During the nineteenth and early twentieth centuries, prehistorians attributed Stonehenge and other stone rings to Egyptian and Mycenean travelers who were thought to have infused Europe with Bronze Age culture. With the development of Carbon-14 dating techniques, the infusion-diffusion conception of British Neolithic history was abandoned and the megalithic monuments of Britain (and Europe) were shown to predate those of the eastern Mediterranean, Egyptian, Mycenean, and Greek cultures.

While the Carbon-14 method provided approximate dates for the stone rings, it was of no use in explaining their function. During the past few decades the orthodox archaeological opinion generally assumed their function to be concerned with the ritual activities and territorial markings of various Neolithic chiefdoms. Research by scholars outside the orthodox bounds of the discipline of archaeology began to suggest an alternative use. In the 1950s and 1960s, the Oxford University engineer Professor Alexander Thom and the astronomer Gerald Hawkins pioneered the new field of archaeoastronomy - the study of the astronomies of ancient civilizations. Conducting precise theodolite surveys at numerous stone rings and other types of megalithic structures, Thom and Hawkins discovered many significant astronomical alignments among the stones. This evidence suggested that the stone rings were used as astronomical observatories. Moreover, the archaeoastronomers revealed the extraordinary mathematical sophistication and engineering abilities that the native British developed before either the Egyptian or Mesopotamian cultures. Two thousand years prior to Euclid's elucidation of the Pythagorean triangle theorems and at least 3000 years before the sixth century AD sage Arya Bhata had "discovered" the concept and value of Pi, the British megalithic builders were incorporating these mathematical understandings into their stone rings. Adding to the revolutionary findings and interpretations of Thom and Hawkins, studies by Aubrey Burl and Benjamin Ray have focused on the stone rings as astronomical observatories and also on their possible "magico-religious" uses.

Stonehenge, the most visited and well known of the British stone rings, is a composite structure built during three distinct periods. In Period I (radiocarbon-dated to 3100 BC), Stonehenge was a circular ditch with an internal bank. The circle, 320 feet in diameter, had a single entrance, 56 mysterious holes around its perimeter (with remains in them of human cremations), and a wooden sanctuary in the middle. The circle was aligned with the midsummer sunrise, the midwinter sunset, and the most southerly rising and northerly setting of the moon. Period II (2150 BC) saw the replacement of the wooden sanctuary with two circles of ‘bluestones’ (dolerite stone with a bluish tint), the widening of the entrance, the construction of an entrance avenue marked by parallel ditches aligned to the midsummer sunrise, and the erection, outside the circle, of the thirty-five ton ‘Heel Stone’. The eighty bluestones, some weighing as much as four tons, were transported from the Prescelly Mountains in Wales, 240 miles away.

During Period III (2075 BC), the bluestones were taken down and the enormous Sarsen stones - which still stand today - were erected. These stones, averaging eighteen feet in height and weighing twenty-five tons, were transported from near the Avebury stone rings twenty miles to the north. Sometime between 1500 and 1100 BC, approximately sixty of the bluestones were reset in a circle immediately inside the Sarsen circle, and another nineteen were placed in a horseshoe pattern, also inside the circle. It has been estimated that the three phases of the construction required more than thirty million hours of labor. Recent studies indicate it unlikely that Stonehenge was functioning much after 1100 BC.

Current theories regarding the purpose of Stonehenge suggest its simultaneous use for astronomical observation and ritual function. By gathering data regarding the movement of celestial bodies, the Stonehenge observations were used to indicate the appropriate days in the annual ritual cycle. In this regard, it is important to mention that the structure was not used only to determine the agricultural cycle, because in this region the summer solstice occurs well after the growing season begins and the winter solstice well after the harvest is finished. Concerning its architectural form and function, scholars have suggested that Stonehenge, especially in its middle and later form, was intended to be a stone (and thereby imperishable) replica of the kind of wooden sanctuary that was more locally common in Neolithic times. What was the nature of the rituals performed at Stonehenge? Ray theorizes that, because Stonehenge is situated in an area rich in burial tombs, it may have had some relevance in burial rituals. Its shape, which resembles that of Neolithic ceremonial buildings, however, points more to its probable use as a shrine for the living rather than for the dead. As a temple for the living, Stonehenge's capacity to determine the dates of the solstices and equinoxes becomes all-important. Throughout the ancient world people have regarded the sun and moon as sacred beings whose cyclical rhythms, with their seasonal strengthening and weakening, had a positive, magical, and rewarding effect upon the life of human beings. Stonehenge and the large number of other stone rings located throughout the British Isles (and the world) are part solar/lunar/stellar observatory and part ritual structure. The mystery remains: Why?

Students of mythology and archaeology will be familiar with the fact that many ancient cultures held festivals on the solstices and equinoxes. The most common interpretation of these festivals is that they are occasions for renewal - the renewal of the people and the land by the celestial powers, and also the renewal of the land and the celestial beings by the agency of human intention, celebration, and sacrifice. The interpretation usually stops here. Discussion may indeed continue regarding the characteristics of the festivals or their sociological function of contributing to the periodic renewal and strengthening of the bonding of a particular cultural group, but the actual depth of the interpretation concerning the times and original meanings of the solstice festivals is rarely pursued. Why would this be so? The answer is quite simple. Almost all those scholars and writers having the academic knowledge to be able to discuss a range of ancient cultures and their mythologies have acquired that information while spending their lives in concrete cities, alienated from the very land-based experience that gives rise to a felt-understanding of the subtle energy rhythms of the natural world. In other words, the tendency of modern urban-based life, in isolating people from the natural world, automatically instills and perpetuates a bias that prevents prehistorians, anthropologists, and archaeologists (and most everyone else) from really understanding the nature-based life of Neolithic cultures. We moderns may (with sometimes quite admirable scholarship) catalogue the behaviors of the ancients, yet an understanding of the motivations and meanings of those behaviors often eludes us. This is especially true regarding the festivals of renewal that occurred on the solstices and equinoxes at the sacred sites.

Prehistorians and archaeologists speak about the ‘myths’ of renewal of ancient cultures, but to the ancient people the festivals were not celebrations of myth but rather celebrations of a current reality. That reality was the periodic energetic effect of solar, lunar, and stellar cycles on human beings, the animal kingdom, and the earth itself. This energetic effect, the increased presence of energy at the sacred sites during particular periods of the astronomical cycles, was the focus of the ritual use of stone rings and so many of the other ancient sanctuaries found around the world.

Based on the preceding material and my own experiences, I interpret Stonehenge to be a structure with multiple purposes. It was a monument, of nearly imperishable quality, erected at a particular site of terrestrial energetic power and celestial significance long known by the peoples of the region. It was an astronomical observation device used to predict, in advance of their occurrence, those particular periods in the annual cycle when the earth energies were most highly influenced and charged by the sun, moon, and stars. It was a temple, built by and for the people, in which festivals of renewal were held at those charged energetic periods determined by astronomical observations. It was a structure built with particular materials (the diorite bluestones brought from 240 miles away and showing evidence of prior use in another sacred structure; the micaceous, green-tinged "altar" stone of unknown origin; and the great Sarsen stones), positioned in such a way as to create a specific form of sacred enclosure which functions as a sort of battery for gathering, storing, and expressing the earth energies of the site on the festival days.

Besides the periodic yearly times (both day and night) of those festivals, which the mathematics, structural engineering, and ground plans of structures like Stonehenge clearly reveal, prehistory has left us, via the myths and legends of the sacred sites, elegant information concerning the nature of the actual practices the pilgrims performed at the festivals. We are given indications of the powers of the sites by old surviving records of even more ancient folk memories. For example, the legendary Merlin tells King Aurelius:

Laugh not so lightly, King, for not lightly are these words spoken. For in these stones is a mystery, and a healing virtue against many ailments. Giants of old did carry them from the furthest ends of Africa and did set them up in Ireland what time they did inhabit therein. And unto this end they did it, that they might make them baths therein whensoever they ailed of any malady, for they did wash the stones and pour forth the water into the baths, whereby they that were sick were made whole. Moreover they did mix confections of herbs with the water, whereby they that were wounded had healing, for not a stone is there that lacketh in virtue of leechcraft.