Staff at St Giles’ Cathedral called paramedics at about 6pm on Thursday, September 20, after finding the mystery man sat in a pew and choking.
He was taken to the Royal Infirmary where he continues to be treated but came around with no recollection of his identity.
Constable Lesley Jack from Howdenhall Police Station said: “This is a very unusual inquiry, as we have a member of the public, who has no idea about who he is, where he is from, or who we can call on his behalf.”
Officers have spoken with the man, who is struggling to communicate and is unable to say where he lives or name any relatives who should be contacted.
Police have now released a description of the man in the hope friends or relatives come forward.
However, his inability to communicate with officers mean he is unable to give permission for a photograph to be released.
The man is described as white, in his early sixties with a medium build, short strawberry blond hair and bluish green eyes and glasses.
He was wearing a blue camouflage hat, Alpha Industria MA1 navy blue bomber jacket, navy blue jumper, red Timberland chequered shirt, green GE Feuchter Passau camouflage trousers and brown Timberland boots.
He also had a Porsche-design silver bracelet watch with a navy clock face and white dial and the days of the week written in Portuguese.
Four tattoos adorn his arms including one of a butterfly and on his upper left and a seahorse on his upper right.
He also has Chinese writing on the inner part of his upper left arm and a similar design on the inner part of his upper right arm.
A visitor to St Giles’ alerted staff trained in first aid after finding the man who appeared to be choking.
Concerned for his safety and unable to revive him, they in turn called paramedics who treated him before taking him to the Royal Infirmary.
He finally regained consciousness in hospital but cannot remember who he is or why he was in the cathedral.
“We sincerely hope this man rediscovers who he is and all ends well,” said a spokesman for Church of Scotland, on behalf of the Royal Mile cathedral.
A trawl of the missing person database has drawn a blank – so officers are hoping a public appeal will reveal some clues and help solve the mystery.
Constable Jack added: “As is standard practice, we have reviewed all relevant missing people and the man does not match the description of
anyone currently reported missing.
“We hope that by issuing this detailed description, someone will recognise this male and come forward to assist with our inquiries.
“If you do believe you can help please contact police immediately.”
Anyone with information can contact Howdenhall Police Station via 101 and quote incident number 2518 of 30th September 2018.