Israeli scientists have used radiometric dating to show when a tunnel in Jerusalem, described in the Bible, was excavated.
By Richard Black
BBC science correspondent
It is believed to be the first time a structure described in the Bible has been accurately dated, and scholars say it will be useful in refining the history of Jerusalem.
Modern-day tourists know the Siloam Tunnel as a half-kilometre-long passage running under Jerusalem's ancient city walls.
Mount of Olives old City Jerusalem
According to the Bible it was excavated by King Hezekiah to carry water from the Gihon spring into the city, securing the supply in times of warfare.
Most scholars believe this happened around 700 BC, though some have contended it is much younger.
Now research led by Amos Frumpkin of the Hebrew University of Jerusalem, reported in the scientific journal Nature, has confirmed the date, which he says is a rare success.
"It's very rare to find things which are mentioned in the Bible that have been confirmed independently by dating," he said.
"First of all it's very difficult to find such structures; it's very difficult to identify them; and usually they are not very well preserved."
Dr Frumpkin's team found plant remains and stalactites in the Siloam Tunnel which they examined using carbon dating and another similar method involving uranium. They confirmed the age at around 700 BC.
Scholars say it is a useful find because it sets an absolute date for a Biblical event, rather than having to rely on interpretations and calculations.
But they say it does not constitute proof that any particular race or community settled in Jerusalem before any other, and shouldn't be used to claim any kind of primacy.
The Siloam Tunnel itself remains a wonder of ancient engineering, excavated by two teams of diggers starting at opposite ends and meeting somehow - no-one knows how - in the middle.
Two thousand seven hundred years after its construction, it is still carrying water into Jerusalem, though this is no longer used for drinking.