ROME (Reuters) - Italian scientists say they have proved Napoleon was not poisoned, scotching the legend the French emperor was murdered by his British jailors.

"Napoleon at Fontainbleau" by Paul Delaroche in an undated image. Italian scientists say they have proved Napoleon was not poisoned, scotching the legend the French emperor was murdered by his British jailors. REUTERS/File

Napoleon’s post-mortem said he died of stomach cancer aged 51, but the theory he was assassinated to prevent any return to power has gained credence in recent decades as some studies indicated his body contained a high level of the poison arsenic.

“It was not arsenic poisoning that killed Napoleon at Saint Helena,” said researchers at the National Institute of Nuclear Physics and the University of Pavia who tested the theory the British killed him while he was in exile on the South Atlantic island in 1821.

The Italian research -- which studied hair samples from various moments in his life which are kept in museums in Italy and France -- showed Napoleon’s body did have a high level of arsenic, but that he was already heavily contaminated as a boy.

The scientists used a nuclear reactor to irradiate the hairs to get an accurate measure of the levels of arsenic.

Looking at hairs from several of Napoleon’s contemporaries, including his wife and son, they found arsenic levels were generally much higher than is common today.

“The result? There was no poisoning in our opinion because Napoleon’s hairs contain the same amount of arsenic as his contemporaries,” the researchers said in a statement published on the university’s website.

The study found the samples taken from people living in the early 1800s contained 100 times as much arsenic than the current average. Glues and dyes commonly used at the time are blamed for high environmental levels of the toxic element.

“The environment in which people lived in the early 1800s evidently caused the intake of quantities of arsenic that today we would consider dangerous,” the scientists said.

One theory was that Napoleon was poisoned accidentally by arsenic vapor from dyes in his wallpaper at Saint Helena, but the study showed there was no massive increase in arsenic levels in his latter years.

“It is clear that one cannot talk about a case of poisoning, but of a constant absorption of arsenic,” the researchers said.

Napoleon had been exiled once before -- on the Italian island of Elba after his failed invasion of Russia. But he returned to France and was finally defeated at Waterloo in 1815 after which he was sent to the much more remote Saint Helena.