Dating dispute over 'oldest Koran'
A dispute over whether a rare early Koran dates from the Prophet Muhammad's lifetime is the latest controversy related to carbon dating. The technique has revolutionised archaeology but is far from an exact science.
In July the University of Birmingham made headlines when it revealed two leaves of worn parchment recently rediscovered in its archives were probably made between AD568 and 645.
Muhammad is traditionally believed to have lived between AD570 and 632.
But there are twists and turns in the tale.
Dr Mustafa Shah, from the Islamic studies department at the School of Oriental and African Studies in London, has questioned this date.
He says the writing itself "is evolved and elaborate, intimating that it represented a mature form" of Arabic writing and places it several decades later.
Francois Deroche, a historian of the Koran at the College de France, also says he has "reservations" about radiocarbon dating of such manuscripts.
But this is just the latest in a series of surprises - and arguments - connected with the method.
Radiocarbon dating - how does it work?
All living things absorb tiny amounts of the radioactive isotope carbon 14 during their lives but this process halts upon death.
This stored C14 then starts to break down at a regular rate and by measuring how much is left in a given sample a calculation can be made of how long it is since the organism died.
American physicist Willard Libby developed the technique in the 1940s and it won him the Nobel Prize.
Radiocarbon dating is limited to objects that are approximately 300 to 50,000 years old due to either there being too little C14 to take a measurement or samples being too heavily contaminated.
The technique was quickly recognised as a watershed in archaeology - but it was not perfect.
Prof Gordon Cook, head of the SUERC Radiocarbon Dating Laboratory, based at the University of Glasgow, said: "The assumption was the amount of C14 in the atmosphere, and the rate at which organisms absorbed it, had been constant throughout history.
"Testing showed this was not true and in fact a sophisticated set of corrections - known as a calibration curve - had to be be developed."
Richard III's skeleton
This was thrown into sharp relief when Prof Cook's team worked on the headline-grabbing dating of Richard III's skeleton.
The first dates came back as AD1430-1460, when Richard was known to have died in 1485.
"But then stable isotope analysis of the bones showed the individual had eaten a lot of seafood," he said. "This gives a reservoir effect that makes the age too old.
"When this was taken into account, the results came in at AD1475-1530. It's not a fiddle or a fudge, it is a proven method for getting the most accurate results."
Where results given by different methods disagree, Prof Cook is clear.
"Carbon dating is backed by scientific rigour, repeatable and verifiable. If someone said analysis of writing or decoration gave a different date, I would ask what backs up that analysis?"
The rectangular cloth bears the faint impression of a naked male body and is claimed by believers to be the burial cloth of Jesus Christ.
However a 1988 radiocarbon testing gave a date of AD1260-1390, consistent with its first recorded appearance in France.
But author Ian Wilson is among those who reject this. He says the section of the shroud tested was likely to have been contaminated.
"The 1988 choice of sample site, where it has historically been most handled, could hardly have been more ill-advised from the point of view of ensuring the least possible contamination," he said.
"That aside, the date range that the carbon dating produced in 1988 simply doesn't make sense.
"The shroud's image is far too subtle, too artistically and anatomically sophisticated, to be the work of any artist, let alone anyone working in the period from which it is supposed to date."
This small island in the eastern Mediterranean was devastated by an immense volcanic eruption in the mid-second millennium BC.
It is a pivotal event for dating in the area and one traditionally seen as a fatal blow to the sophisticated Minoan civilisation. It has even been linked with the stories of the parting of the Red Sea in Exodus and the legend of Atlantis.
But, as Dr Michael Dee, Leverhulme Fellow from the University of Oxford's School of Archaeology, explains, its own date is a matter of fierce debate.
"Historians have traditionally put the eruption at BC1500 but carbon dating, using organic remains from the island, has placed it between BC1627 and 1600.
"That is six generations earlier and it overturns the idea of crippled societies being overrun. It gets quite heated."
Dead Sea Scrolls
Some examples are less controversial and more of a revelation.
Stumbled upon in desert caves in the West Bank in 1946, the fragile documents were initially handed around antiquities traders and initially thought to be of little value.
But, when first studied by experts, the writing was noted to be of an early style, perhaps from the 2nd Century AD.
In one of the first major carbon dating tests, linen from the same caves as the scrolls was found to date from AD33, plus or minus 200 years. This date showed they were the oldest Hebrew texts in existence and of fundamental importance to Biblical scholars.
Further testing of the scrolls and analysis of the text has backed this date up.
Discovered poking out of an Alpine glacier in 1991, it was immediately obvious the iceman was old. But how old?
The first experts, from the University of Innsbruck, looked at the copper axe he carried and roughly estimated he had died 4,000 years ago.
Carbon dating returned a period of 3359 to 3105BC - more than 5,000 years ago.
This result pushed the back the date for use of copper tools back by 500 years and improved understanding of how early European human society developed.
La Bella Principessa
Although for years it was believed to be a German portrait from the early 1800s, La Bella Principessa was hailed in 2010 as a lost work by the 15th Century master Leonardo da Vinci.
Opposing art historians clashed over styles and materials, with supporters suggesting the work was created in 1495, predating the Mona Lisa.
Carbon dating of the vellum backing gave the likely date range as AD1440 to 1650, leaving the jury out on its authenticity.
In 1998 the portrait sold for just under £15,200 ($22,000). If it was shown to be a genuine Leonardo, it would be worth somewhere in the region of £103m ($150m).
Inside Out West Midlands featured the story of the Birmingham Koran and is now available on iPlayer.