On the 18th December, 1985, three pilgrims, who had arrived on Holy Mount Athos the previous day, visited the library of the Bulgarian monastery of St.Georgi Zograph.

After distracting the attention of Father Pahomii, the librarian, they replaced the original manuscript of the "Slav Bulgarian History" with a copy which had been prepared in advance. They seal the original in a plexiglass container.

Two of the pilgrims were operatives from the residencies of the First Main Directorate of State Security in Thessalonica and Athens, the third was a diplomat from the embassy of the People's Republic of Bulgaria in Athens. For State Security this was one of their biggest operations abroad.

The theft of the original manuscript of Paisii’s history was one of the most carefully prepared and planned special operations by the First Main Directorate (FMD) of the State Security Service (SSS) in more than 13 years. This is clearly suggested by the code name of the operation to steal the manuscript – "MARATHON".

The sensational discovery of documents referring to the theft of the "Slav Bulgarian History" from the Zograph Monastery on Holy Mount Athos were brought to public attention by Hristo Hristov, an investigative journalist and founder of the site "desebg.com". Hristo recently discovered in the archives of the State Security Service the plans and reports of the top secret "MARATHON" operation.