The mystery behind the identity of a syphilis-riddled women whose mummified body was buried beneath a Swiss church has finally been solved after puzzling experts for 40 years.
A team of international scientists carried out genetic analysis of the body – only to discover the woman is an ancestor of Foreign Secretary Boris Johnson. She is his great-great-great-great-great-great-great-grandmother.
The body was unearthed in 1975 while renovations were being carried out at the Barfüsser church in Basel.
The remains were well preserved because of a high mercury content, which often signifies a person had been treated for syphilis – it was standard treatment for the sexually transmitted disease from the late 1400s, though was deadly in itself.
The burial site, in front of the church’s altar, indicated that the corpse belonged to an individual with high status. But there was no gravestone, and her identity was unknown.
Local historians were aware that members of Basel’s wealthy families were buried in and around the church. Some were named in records and some had clearly marked gravestones. But not the mummy.
The real breakthrough came when recently discovered archives revealed the body had been dug up once before, in 1843.
Those records led researchers to suspect the woman was a member of the prominent Bischoff family.
Now researchers at Basel’s Natural History Museum have confirmed her genealogy and pinpointed her identity.
DNA extracted from the mummy’s toe revealed she is Anna Catharina Bischoff, who was born in 1719.
She married a pastor and gave birth to seven children, though only two of them survived to adulthood.
She spent most of her life in Strasbourg but moved back to Basel for her final five years.
She had contracted syphilis, possibly through treating sufferers of the disease, and it was likely the mercury treatment that caused her death in 1787.
One of her surviving children, Anna Katharina Gernle, married German aristocrat Christian Hubert Baron Pfeffel von Kriegelstein.
Five generations later, Marie Luise von Pfeffel got hitched to Stanley Fred Williams, whose daughter Yvonne married Osman Wilfred Johnson Kemal.
Their son was Stanley Johnson, father of Alexander Boris de Pfeffel Johnson.
Mr Johnson reacted to the discovery on social media.
He tweeted: “Very excited to hear about my late great grand ‘mummy’ – a pioneer in sexual health care. Very proud.”
Museum experts have said the mummy is the best preserved and “most enigmatic” in Switzerland.