He and I lay on our bellies on either side of a massive metal door separating two sections, A and B, in the Robben Island Prison. I had just arrived there in early 1974 after being sentenced in the Grahamstown Supreme Court the previous year for my activities in the Black People's Convention.
I was a 25-year-old youngster then, lying in that position with an older man on the other side, and other prisoners on either side of the door watching out for the warders, as he welcomed me to prison.
Rather odd, is it not? Being welcomed into a prison? But he soon explained that my arrival there meant that our people had not abandoned the struggle.
Undesirable as they were, detentions, trials and imprisonments – especially of younger people – meant that political activism did not die with the imprisonment of his generation.
As students, cutting our political teeth in the South African Students' Organisation, we eulogised the likes of Nelson Mandela, Walter Sisulu, Robert Sobukwe and others. We sang songs about them and composed moving poems that we recited at our occasions.
Little did I imagine that my first encounter with one of them would be in a horizontal position, peering at him through a square hole at the bottom of that metal door.
That contact made, we continued to interact, mainly through clandestine correspondence, even after I was moved to another section, far away from his.
The letters between us would arrive in the form of a worm-like thing, a sheet of paper rolled tightly and neatly into a "finger", and then wrapped with Sellotape to enable it to "travel" in soft porridge.
The prisoners working in the kitchen were the "postmen". This was the mode of correspondence in order to beat the prohibition of communication between prisoners in different sections.
This contact was broken by my release from Robben Island in 1978. It saw me serving a banning order, fleeing into exile and coming back in 1994 to a South Africa in which Nelson Mandela was president. It was a break of more than 16 years.
Although the Azanian People's Organisation (Azapo) had not taken part in the negotiations and the subsequent elections, Mandela invited us now and then for briefings on what he thought were issues of national importance.
A memorable encounter was at the unveiling of the Steve Biko statue in East London in September 1997.
As we walked side by side to the podium, he kept asking me to wave to the crowds. I would do that and then stop. He would turn around and say: "Mosibudi, wave! Wave!" I would oblige and then stop.
I was relieved when we finally ascended the podium.
But that was Mandela: warm and going out of his way to connect with people.
Sitting in Harare, Zimbabwe, on the day of his release, my comrades in the Black Consciousness Movement of Azania (BCMA) and I watched him on television as he triumphantly walked out of prison. The Zimbabwe Broadcasting Corporation had no presence in South Africa at the time, but was given special permission by its government to cover the event.
His release confirmed the rumours that secret negotiations were taking place, and that Mandela was at the centre of it. We were nervous and anxious. We did not know what the implications would be.
Azapo and the BCMA did not like the political settlement that was later reached with Mandela at the helm. We reckoned it would do nothing to tackle the deliberate impoverishment of the majority black population that was consolidated over centuries of colonialism and apartheid.
There is a sense in which we feel vindicated by the turn of events. We have political freedom and rights, but the poverty of the majority endures and worsens. This might not be due to the settlement alone, but its structure played a major role in that regard. And if no dramatic action is taken, that settlement might unravel under the tension induced by poverty existing side by side with opulence.
In those circumstances, the revolution might just have been postponed.
But then, what would South Africa have looked like today if his intervention did not result in the settlement we have? Would we be like another Syria, Libya or Egypt? Would we perhaps look like Somalia, where the state has failed and life is unlivable?
Would that be better than the settlement we have in South Africa?
We will never know, but we can certainly do something to bolster the current arrangements so that the country is enabled to address these unsustainable levels of inequality.
Ours is a middle-income country that is blessed with enormous natural resources. Prudent and honest handling of these can lead us to a better society. We would have used the settlement as a platform to build a better country for ourselves and future generations.
Mandela has done his part. May his soul rest in peace!
Mosibudi Mangena is the former president of the Azanian People's Organisation