In a feat of laboratory sleuthing, scientists on Thursday provided a background to a mysterious Bronze Age teenager who died in modern-day Denmark 3,400 years ago.
The "Egtved Girl," uncovered at a village in the Jutland peninsula, was probably born in southwestern Germany and may have been married off to cement ties between powerful families, they said.
One of Denmark's proudest relics, the Egtved Girl was found in 1921 at a burial mound, inside an oak coffin that dates her interment to a summer's day in the year 1370 BC.
She was aged between 16 and 18 at the time of death and would have been around 1.6 metres (five feet three inches) tall. Her bones had dissolved in the acidic water in the coffin, but her blond hair, teeth, well-trimmed nails and parts of the brain and skin were extraordinarily preserved, along with her woollen garments and a disc-shaped bronze belt plate symbolising the Sun.
Buried alongside her head was a small container with some cremated bones of a five- to six-year-old child.
The site and her clothes clearly pointed to a person who was cherished and of high rank. But who was she? And where did she come from?
Seeking an answer, researchers led by Karin Margarita Frei from the National Museum of Denmark and Centre for Textile Research analysed the precious find for levels of the radioactive element strontium.
Strontium exists naturally in the Earth's crust, with its radioactivity varying in strength according to location. In humans and animals, the element becomes absorbed through local water and vegetables.
Thus by measuring levels of the isotopes in ancient remains, scientists can gain a useful clue of where that individual or animal had lived.
One of the girl's first molars, a tooth that was fully formed when she was aged three or four, had a strontium signature in the enamel that showed she had not grown up in Jutland, the study said.
Instead, it matched a "geologically older" region -- most probably the Black Forest area of southwestern Germany, a whole 800 kilometres (500 miles) to the south.
Strontium levels in the girl's 23-cm (10-inch) -long hair and her nails were also revealing.
Around 13 to 15 months before her death, she stayed in a place with a strontium signature "very similar" to where she was raised. She then likely moved to another location -- possibly Jutland -- and after spending nine or 10 months there travelled back home. She stayed there for four to six months before travelling to what is now Egtved, but died about a month later.
There are other candidates for the girl's home region, including Sweden and Norway and the geologically old Danish island of Bornholm.
But southwestern Germany is by far the best bet, according to the study, which appears in the journal Scientific Reports.
The wool in her clothing has strontium levels that vary greatly from thread to thread, said Frei.
"This proves that the wool was made from sheep that either grazed in different geographical areas or that they grazed in one vast area with very complex geology," she said. "Black Forest's bedrock is characterized by a similarly heterogenous strontium isotopic range."
Other clues also help to build an identity for the enigmatic girl, said Kristian Kristiansen of the University of Gothenburg, Sweden.
"In Bronze Age western Europe, southern Germany and Denmark were the two dominant centres of power, very similar to kingdoms," he said.
Trade between Jutland and southwestern Germany at the time was lucrative.
An alloy of tin and copper, bronze was the wonder metal of the age, made by metallurgists in Greece and the Middle East.
In return, these regions in Mediterranean coveted Danish amber, valuing the mineral as much as gold. Middlemen in Germany acted as the go-between in the trade.
"We find many direct connections between the two (regions) in the archaeological evidence," said Cristiansen. "My guess is that the Egtved Girl was a southern German girl who was given in marriage to a man in Jutland so as to forge an alliance between two powerful families."