The relationship achieved a degree of worldwide fame when, in 1981, Glasgow awarded Mr Mandela the freedom of the city. At the time, he was still in jail, courtesy of the white South African regime. Mr Mandela later said that Glasgow's decision reminded him the world had not forgotten the ANC's struggle.
He was freed in February 1990, walking out of Victor-Verster Prison into a global media whirlwind, a free man for the first time in nigh on three decades. No longer was he prisoner number 46664 - even if the number did become an enduring part of the Mandela iconography.
A visit to Glasgow was arranged for February 1993, prompting councillor Jean McFadden, then leader of the Labour-controlled council, to say: "Mr Mandela is coming here to be honoured, but the honour is ours. He is a symbol of the fight for equality and freedom throughout the world."
The trip was cancelled on doctors' orders, but the indefatigable Mandela finally arrived in Scotland that October.
The day the 75-year-old statesman arrived, it was the only show in town. Not even the rain could dampen the overwhelming sense of occasion in George Square, which lay within sight of Nelson Mandela Place, the street re-named in his honour in 1986.
Ordinary Glaswegians, students and activists with ANC banners, Labour MPs, pensioners, young couples, all were drawn to the square.
"He did not smile: he positively beamed," a report in The Herald noted. "His eyes, no longer haunted by his years in prison, sparkled with mischief and humour."
Mr Mandela said: "People of Glasgow, I am now free to be with you. I am free and I am here today to thank you. But I am still denied the most fundamental of freedoms in my own country - the right to vote. But I bring a message of hope. We have made great progress towards our goal of one person, one vote."
He earned a huge cheer when he said right would prevail in South Africa "because there are men and women who regard the whole world as the theatre of their efforts and their battlefield".
Watched by veteran anti-apartheid campaigner Archbishop Trevor Huddleston, Mr Mandela held the hand of 14-year-old Glasgow schoolgirl Lesley Paterson, who had won a competition in The Herald's sister paper, the Evening Times, to meet him.
"We want young people like her," he told the crowd. "No cause can fail if it is supported by the youth, and that is something to which she has responded."
The youngster, needless to say, was awestruck. "It was great," she enthused. "He was fantastic."
Mr Mandela delighted onlookers by dancing with a South African singer, Mara Louw, as she sang a Sowetan pop song called Turn Me Around.
As the formalities ended, he left the stage and plunged himself into the cheering throng: a never-to-be-forgotten moment for those who were fortunate enough to be in the vicinity.
Earlier in the day, at a more formal ceremony in the City Chambers, Mr Mandela had met some 400 dignitaries and guests, representing not only Glasgow but all the other towns and cities that had offered him their freedom, including Aberdeen, Midlothian and Dundee.
Declaring that Glasgow would always enjoy a distinguished place in the records of the international campaign against apartheid, he went on: "The people of Glasgow were the first in the world to confer on me the Freedom of the City at a time when I and my comrades in the ANC were imprisoned on Robben Island serving life sentences which, in apartheid South Africa, then meant imprisonment until death."
That year was an important one for Mr Mandela: not only was he able to visit Britain, but he also received the Nobel Peace Prize, alongside FW de Klerk, then president of South Africa.
Four years later Mr Mandela visited Edinburgh as part of a Commonwealth Heads of Government meeting. He received the Freedom of the City on October 27, 1997, from the Lord Provost at the time, councillor Eric Milligan.
Mr Milligan said Mr Mandela was being honoured for his "personal lifelong fight for equality for the people of South Africa'' and his nation's struggle for peace and justice. "We are proud," he added, "to honour someone whose personal strength, compassion and dignity has made him admired around the world."
The charismatic Mr Mandela even got away with what seemed to be a breach of protocol when he arrived at the city's International Conference Centre after the Queen, for the opening of the Commonwealth summit.
At public events graced by royalty, everyone is supposed to assemble before the royal personage arrives.
The Queen was chatting with Tony Blair in the lobby when the then Prime Minister glanced round and broke away to welcome South Africa's president. "Hello, Tony, how are you?'' cried Mr Mandela. Together, they moved inside and, as they neared the Queen, he said: "I'm terribly sorry, Your Majesty, that I'm late."
It worked like a charm. Mr Mandela, 78, and dressed in a trademark tribal-print shirt, was rewarded with a wide smile.
In June 2002, Mr Mandela, by now the former President of his country, was back in Glasgow again, but this time, a few miles to the east of George Square.
At Barlinnie Prison, he spent an hour with Abdelbaset Ali Mohmed al Megrahi, the man who had been convicted of the Lockerbie bombing. Speaking at the prison, he said Megrahi was suffering "psychological persecution" and called for another appeal hearing, but stopped short of saying he was the victim of a miscarriage of justice.
Mr Mandela later met families of some of the Lockerbie dead.
In August 2009, in the wake of the Scottish Government's controversial decision to free the then terminally ill Megrahi, he expressed his appreciation.
A letter to the Scottish Government from Professor Jake Gerwel, chairman of the Mandela Foundation, said: "Mr Mandela sincerely appreciates the decision to release Mr al-Megrahi.
"Mr Mandela played a central role in facilitating the handover of Mr al-Megrahi and his fellow accused to the United Nations in order for them to stand trial under Scottish law in the Netherlands. His interest and involvement continued after the trial after visiting Mr al-Megrahi in prison.
"The decision to release him now, and allow him to return to Libya, is one which is therefore in line with his wishes."
There is one last footnote to that day in George Square in 1993: in 2010, when Billy Connolly was made a Freeman of the City of Glasgow, tributes were made by a clutch of previous honorees, among them Nelson Mandela himself. "I wish Mr Connolly my congratulations at the high honour being bestowed on him," he said. "Welcome to a very special club indeed!"