A signed letter from Muhammad Ali to Nelson Mandela sold for £7,200 ($8,995) over the weekend.
The lot was among the highlights of a sale at Henry Aldridge & Son in Devizes, UK on December 17.
Ali gives his condolences to Mandela following the murder of his ANC colleague Chris Hani
It's dated to April 13, 1993 and offers Ali's condolences following the murder of Chris Hani, Mandela's colleague in the armed wing of the African National Congress (ANC).
Hani was shot dead outside his home in Boksburg by a Polish white supremacist named Janusz Walus.
Investigations after the assassination revealed Walus' links to senior figures in the ruling South African Conservative Party.
Riots followed. Mandela himself made an appeal for calm: "Now is the time for all South Africans to stand together against those who, from any quarter, wish to destroy what Chris Hani gave his life for - the freedom of all of us."
Hani's death proved a catalyst for change in South Africa.
While apartheid had officially been abolished in 1991, its architects remained in power.
A year later the country held its first free and fair elections, which Mandela and the ANC took with a landslide 62.6% of the popular vote.
The apartheid era was finally at an end.
The letter is on paper headed with the name of the hotel Ali was staying at in Johannesburg. He met with Mandela during his time in South Africa and attended Hani's funeral.