By Peter Biles
BBC News, Johannesburg
Mr Mandela will celebrate his 90th birthday later this year
Former South African President Nelson Mandela has met a group of men and women with whom he was on trial during the struggle against apartheid.
Mr Mandela was an accused on three occasions during that period, including the famous Rivonia Trial, when he was sentenced to life imprisonment.
Twenty surviving defendants met the ex-President in Johannesburg.
The historic reunion was part of the celebrations for Mr Mandela's 90th birthday later this year.
It has long been Mr Mandela's wish to be reunited with the survivors of the trials that were landmark events in the 1950s and 60s.
Now they have been able to share their memories about the early efforts to end white domination in South Africa.
Of the more than 150 men and women who went on trial for treason with Nelson Mandela in 1956, only 25 are still alive.
Now in their 70s and 80s, many of these well known activists are increasingly frail.
Dennis Goldberg, who was among those in the dock with Mr Mandela at the Rivonia Trial in 1964, paid tribute to his former colleagues.
"The people I met are people who selflessly committed themselves to building a free South Africa with justice and democracy, and a better life for all our people. And that struggle continues," he said.
The reunion was made possible with the help of Sweden which gave extensive support to the anti-apartheid movement from 1960 onwards.
Mr Mandela will turn 90 in July. He appears to be in reasonable health, but now makes far fewer public appearances.