A new study has revealed that the heart of Richard the Lionheart was preserved with mercury, mint and frankincense, among other sweet-smelling plants.
The study is the first biochemical look at the heart of Richard I, who died in 1199.
As it was common practice at the time, the king's heart was removed and mummified separately from the rest of his body. It rested in a reliquary at Notre Dame in Rouen for centuries before its rediscovery in 1838, Fox News reported.
"The aim was to approach the odor of sanctity," Charlier told LiveScience.
Richard I of England began his rule in 1189. He spent two years in captivity in Europe, much of that time being held for ransom by the Holy Roman Emperor.
Later, the tale of Richard I's ransom would be folded into folk tales about Robin Hood, casting Richard I as a benevolent absent monarch and his brother John as a tax-happy usurper.
On March 25, 1199, years after the kidnapping, Richard sustained a crossbow wound in Chalus, France, and died 12 days later of gangrene.
His abdominal organs were removed and interred in Chalus, while his body went to rest at Fontevraud Abbey in France. His heart was embalmed and placed in its own casket and taken to Notre Dame in Rouen.
This division of the body was used to symbolize and mark Richard I's territory, Charlier said.
However, no ancient texts remain to record how the embalming process was done.
The heart rested in Rouen until July 1838, when a local historian discovered a lead box inscribed, "Here is the heart of Richard, King of England."
The heart itself had been reduced to dust in the preceding centuries; all that the box contained was a brownish-white powder.
It was this powder that Charlier and his colleagues tested. They found a variety of compounds, including traces of the proteins found in human heart muscle.
They also observed tiny fragments of linen, suggesting that the heart was wrapped before placement in the box.
Some metal compounds, including lead and tin, likely seeped into the powder from the lead box. Others were probably used in the embalming process.
In particular, the researchers detected mercury, which has been found in other medieval burials and was probably used as an embalming agent.
The analysis also turned up pollen from a variety of plants: myrtle, daisy, mint, pine, oak, poplar, plantain and bellflower.
Some of these, including poplar and bellflower, would have been blooming in April when Richard the Lionheart died; their pollen may have simply settled out of the air into the casket.