Genealogists identified it as Anna Catharina Bischoff, the great-great-great-great-great-great-grandmother of the Foreign Secretary.
According to the BBC, initial testing of the wooden coffin suggested it was dated from the 16 century, but after comparing the mummy's DNA with that of living descendants of the Bischoff family, her identity became clear - there was a 99.8 percent probability that the descendants and the mummy were from the same maternal line.
Of course, as we now know, mercury is highly toxic and she is suspected to have died from mercury poisoning.
Scientists in the Swiss city of Basel have finally identified a mysterious mummified body after more than 40 years and established that the woman was an ancestor of United Kingdom foreign secretary Boris Johnson.
Another clue: her body was riddled with mercury - a standard treatment for syphilis from the late 15th to the 19th Century.
DNA extracted from the mummy's toe has revealed she was Anna Catharina Bischoff, UK Foreign Secretary Boris Johnson's great-great-great-great-great-great-great grandmother.
Archive records emerged which showed she had been discovered before in 1843 and they led historians to believe she was a member of the established Bischoffs family.
Bank recap to be dependent on performance, reforms, says Finance Ministry official
Indian Overseas Bank, which received Rs 4,694 crore and was the first to face PCA, welcomed the move. The government will issue recapitalisation bonds of 6-10 years maturity.
Now the scientists and the historians were sure: the mummy was none other than Anna Catharina Bischoff.
However, his Swiss relative, had a more humble life. She also appears to have been well-fed. Only two of those kids, both daughters, lived to see adulthood - and researchers say just one was known to have married and had children of her own.
After her husband's death, she returned to Basel and underwent treatment in a bid to cure her of her disease.
The Foreign Secretary has previously spoken about his ancestors as "posh toffs" after learning about their upper class origins.
"This discovery means that Boris Johnson is not only distantly related, albeit very far removed, to the present Royal Family but also to all the royal houses of Europe, including the Swedish and Dutch royal families, as well as the Romanoffs", the BBC said at the time.