SINN Féin's £1.5 million donor had his ashes buried in west Belfast in a "solemn ceremony" attended by Gerry Adams.
Retired English mechanic William Hampton's ashes are interred in a grave plot in Hannahstown Cemetery, The Irish News can reveal.
An image has emerged showing former Sinn Féin leader Mr Adams and the party's West Belfast MP Paul Maskey among those at the interment ceremony.
Mr Hampton's political donation, which he left in his will, is considered the largest in the north's history.
His gravestone reads: "True friend of Ireland. Remembered by his friends and comrades in Sinn Féin."
Mr Hampton (82) died in January last year in Pembrokeshire in Wales, where he was living in a nursing home.
He had inherited money from his father, Ted, who had extensive business interests in Fenstanton, Cambridgeshire.
Friends say Mr Hampton, who had no known links to Sinn Féin or Irish republicanism, bequeathed the record-breaking sum to hit back at the British establishment.
Irish News columnist Jim Gibney was among those who attended Mr Hampton's interment ceremony at Hannahstown, which he said took place on August 9 last year.
He described it as a "solemn ceremony" and said the only speaker was Dessie Mackin – an executor to Mr Hampton's will and a Sinn Féin treasurer when the will was made.
"What happened was that a group of republicans, Belfast-based republicans, attended a ceremony for Billy Hampton," he said.
"It was a solemn occasion given the circumstances, that we were there to pay tribute to him.
"A few words of thanks were said to him by Dessie Mackin, and who thanked him as a supporter of Sinn Féin and as a supporter of a united Ireland."
Mr Gibney said he understood Mr Hampton had asked to be buried there by republicans and said the party donor was "treated with respect".
When Mr Hampton penned his will in 1997, his address was listed as 'no fixed abode' and stated he was living in a mobile home in the south-west of Ireland.
It has also been reported he had a history of serious mental health problems, and in 2000 wrote a letter saying that Sinn Féin no longer spoke to him "for security reasons".
TUV leader Jim Allister has asked the National Crime Agency to investigate the donation and the origins of Mr Hampton's wealth.
However, Sinn Féin has insisted it complied with all Electoral Commission rules and regulations, with vice-president Michelle O'Neill saying there is "nothing to see here".
