Bones found in a German cathedral belong to the granddaughter of Saxon king Alfred the Great, experts confirmed yesterday.

Body parts excavated in Magdeburg Cathedral in 2008 are those of Saxon princess Eadgyth, who died more than 1,000 years ago.

They are the oldest surviving remains of an English royal burial, according to experts at the University of Bristol who analysed the skeletal fragments to piece together a snapshot of the princess's life.

Princess Eadgyth was married off to Otto I, the Great, in AD 929 by her half brother Athelstan, who was the first king to rule all of England.

As wife of the king of Saxony, she lived most of her married life in Magdeburg, capital of Saxony-Anhalt, and had at least two children.

She died in AD 946 aged about 36 and was buried in the monastery of St Maurice in Switzerland.

Her bones were moved at least three times before being finally interred in an elaborate tomb in Magdeburg Cathedral in 1510.

Two years ago, German archaeologists opened the tomb, expecting it to be empty.

To their surprise, they found it contained a lead box bearing the inscription: "The remains of Queen Eadgyth are in this sarcophagus".

When they opened the coffin they discovered bone fragments wrapped in silk.

It is thought some of the missing body parts, including hands and feet and much of the skull, were probably taken by mediaeval relic hunters.

An analysis of the remains by Kurt Alt at the University of Mainz established they were those of a female who died aged between 30 and 40.

Prof. Alt also found evidence that the woman was a frequent horse rider and ate a high protein diet with large amounts of fish, which suggested she had enjoyed an aristocratic lifestyle.

But the challenge facing the archaeologists was to prove that the bones, which had been moved several times and could easily have been replaced with others, were really those of Queen Eadgyth.

Director of the project Harald Meller, of Germany's State Office for Heritage Management and Archaeology, said: "Mediaeval bones were moved frequently and often mixed up, so it required some exceptional science to prove that they are indeed those of Eadgyth.

"It is incredible that we have been able to do this using the most recent analytical techniques."

Crucial evidence came from the study of teeth preserved in Eadgyth's upper jaw.

Scientists at the University of Bristol's Department of Archaeology and the Institute of Anthropology at Mainz University measured strontium and oxygen isotopes that mineralise in the teeth as they form.

These isotopes depend on the local environment and its underlying geology, which are then effectively "locked" into the teeth.

By studying tiny samples of tooth enamel, researchers worked out that the woman must have spent the first 14 years of her life in the chalk regions of southern Britain.

Alistair Pike, senior lecturer at the University of Bristol, explained: "Strontium isotopes on tiny samples of tooth enamel have been measured. By micro sampling, using a laser, we can reconstruct the sequence of a person's whereabouts, month by month up to the age of 14."

They found the isotope results exactly matched historical records of Eadgyth's childhood and adolescence in Wessex.