David Lytton, 67, from London, was discovered at Dove Stone Reservoir in Greater Manchester on 12 December 2015.
It took police more than a year to establish his identity and a "provisional" cause of death was given as "strychnine poisoning".
A full inquest is scheduled to begin at Heywood Coroner's Court at 14:00 GMT.
The death sparked worldwide interest as a police investigation was launched to identify the body of the man, first nicknamed Neil Dovestones by mortuary workers at Royal Oldham Hospital.
It was discovered Mr Lytton had lived in Pakistan for 10 years and had flown to London Heathrow, two days before his body was found.
He had no wallet, phone or documents and was identified from photos from a passenger list and picked up on CCTV in London.
His identity was eventually confirmed as a result of a DNA match with a relative in January.
It later emerged he had changed his name from David Lautenberg, the name he was born with in 1948.
Police believe he took his own life.
Det Sgt John Coleman described the case as "unlike anything I have ever known" in 20 years as a police officer.
Speaking after Mr Lytton's identity was finally established, he said: "Possibly the biggest question still remains, which is why a man with no obvious connection to Saddleworth chose to head there after returning from Pakistan."
The mystery gave rise to a number of theories about Mr Lytton's death, which were later discounted.
There was speculation he could have been making a final journey to the site of a plane crash in 1949 which killed his family, while a man from Northern Ireland contacted police to say he could be missing Hugh Toner, from Newry, who disappeared in 1994.
The death of a man whose body was found in mysterious circumstances on Saddleworth Moor will be examined at an inquest later.