Mandela was in prison for 27 years, oppressed his whole life before and after that, and once he gets power, his watchwords? Truth and Reconciliaton.
That's why he deserved the Nobel Peace Prize, because with any other leader (just pick a country on the same continent, Zimbabwe's right next door) that situation turns into a shitshow at that point.
The fact that he was in the ANC isn't what makes him notable, plenty of other guerilla leaders in Africa who threw out colonialists or white minority rule. That's not why we're talking about him. What he did when he won made him notable.
The "he wasn't peaceful" idiots on this thread are either incapable of seeing the big picture or fighting some dumb US domestic political battle.