New radiocarbon dates of human cremation burials at Stonehenge indicate that the monument was used as a cemetery from its inception just after 3000 B.C.

until well after the large stones went up around 2500 B.C.

Many archaeologists previously believed that people had been buried at Stonehenge only between 2700 and 2600 B.C., before the large stones, known as sarsens, were raised. The new dates provide strong clues about the original purpose of the monument and show that its use as a cemetery extended for more than 500 years.

This is one of the discoveries made by the Stonehenge Riverside Archaeological Project supported by National Geographic under the leadership of Professor Mike Parker Pearson of the University of Sheffield. Dr Joshua Pollard of Bristol University's Department of Archaeology and Anthropology is one of the Directors of the Project.

Professor Parker Pearson said: "It's now clear that burials were a major component of Stonehenge in all its stages. Stonehenge was a place of burial from its beginning to its zenith in the late third millennium B.C. The cremation burial dating to Stonehenge's sarsen stones phase is likely just one of many from this later period of the monument's use and demonstrates that it was still very much a 'domain of the dead.'"

The earliest cremation burial dated - a small pile of burned bones and teeth - came from one of the pits around Stonehenge's edge known as the Aubrey Holes and dates to 3030-2880 B.C., roughly the time when Stonehenge's ditch-and-bank monument was cut into Salisbury Plain.

The second burial, from the ditch surrounding Stonehenge, is that of an adult and dates to 2930-2870 B.C. The most recent cremation comes from the ditch's northern side and was of a 25-year-old woman; it dates to 2570-2340 B.C., around the time that the first arrangements of sarsen stones appeared at Stonehenge.

This is the first time any of the cremation burials from Stonehenge have been radiocarbon dated. The burials dated by the team were excavated in the 1950s and have been kept at the nearby Salisbury Museum.

Another 49 cremation burials were dug up at Stonehenge during the 1920s, but all were put back in the ground because they were thought to be of no scientific value. Archaeologists estimate that up to 240 people were buried within Stonehenge, all as cremation deposits.

Professor Andrew Chamberlain, a specialist in ancient demography at the University of Sheffield, theorizes that the cremation burials represent the natural deaths of a single elite family and its descendants, perhaps a ruling dynasty. One clue to this is the small number of burials in Stonehenge's earliest phase, a number that grows larger in subsequent centuries, as offspring would have multiplied.

Another is the graves' placement in such an impressive monumental site. "I don't think it was the common people getting buried at Stonehenge - it was clearly a special place at that time," Professor Parker Pearson said. "One has to assume anyone buried there had some good credentials. The people buried here must have been drawn from a very small and select living population.

Archaeologists have long speculated about whether Stonehenge was put up by prehistoric chiefs - perhaps even ancient royalty - and the new results suggest that not only is this likely to have been the case but that it also was the resting place of their mortal remains."

Besides conducting the radio carbon dating, this season the archaeologists excavated houses at nearby Durrington Walls, precisely dating Stonehenge's cursus - the ditched enclosure that has long puzzled archaeologists - and made new discoveries about the "Cuckoo Stone" and the timber monuments south of Woodhenge.

Much of the focus for the fifth of the eight-year Stonehenge Riverside Project, was at Durrington Walls, Stonehenge's sister henge about 2 miles away. Professor Parker Pearson believes Durrington was built to accommodate the living, in contrast to Stonehenge's more sombre purpose as a monument to the dead.

Last year the project archaeologists announced the discovery in 2006 of a large seasonal village where Stonehenge's builders are thought to have lived some 4,600 years ago. This season (2007) the team excavated four of those houses that once sat on a hillside, one of them especially well-preserved.

Excavation of it turned up a wall made of cobb - a mixture of broken chalk and chunky plaster - that is the oldest such wall found in Britain. The others houses were found to be mostly of wattle-and-daub construction.

In the well-preserved house, which measured 4.8 by 5.2 meters (about 16 feet square), researchers unearthed bits of Stone Age life - flint tools, the end of a broken-off dress pin and two teacup-sized pits in the house's corners containing tiny sharp chippings of flint, apparently swept there by the residents. Imprints of beds and a dresser also were visible around the edges of the floor. In the house's centre, by the remains of an oval-shaped hearth, two thick grooves are visible in the floor, right in that part of the fire where the floor has been stained with ash.

The team also uncovered several houses along a broad avenue that links Durrington Walls with the nearby River Avon. These were three-sided structures with fireplaces, perhaps used by spectators at processions that once moved up and down the avenue to the river.

The season's work leads Professor Parker Pearson to believe that Durrington Walls was made up of a large, circular village of more than 300 houses, making it the largest village of its time in northwest Europe. "We think that both men and women and presumably children were living there - everybody seemed to have been involved in the building of Stonehenge," he said.

Preliminary results of environmental analyses suggest this was a seasonal settlement. The absence of certain items, such as newborn pigs and cattle, together with archaeological evidence of culling of pigs in the midwinter period, suggest that people journeyed to the site with prepared foodstuffs and animals only at certain times of the year.

Along the cliff top south of the timber monument known as Woodhenge, the archaeologists, led by Dr Joshua Pollard of the University of Bristol, discovered two oval-fenced areas enclosing dramatic, monumental timber structures, each anchored by four large posts. "These obviously were not domestic buildings," Dr Pollard said. "Their purpose is uncertain, but it's possible they supported raised platforms where bodies of the dead were left to decay."

"All in all, we're finding that Stonehenge was a sophisticated society with great achievements," Professor Parker Pearson said. "I doubt they realized they would create such a great mystery for the world to come."