In an extraordinary bid to pull him away from the influence of Chief Mangosuthu Buthelezi, the king's uncle and chief adviser, Mr Mandela, himself a Xhosa chief, repeated the offer of status and powers to be granted to the king 'which are exactly the same as those enjoyed by the Queen of England'. This offer was made by the ANC last week, but at the rally he read out the details.
He made the people, all of them Zulu, all of them ANC supporters, stand up and repeat the traditional greeting to the king. He reminded the thousands of supporters at the Umlazi stadium that he had been legal adviser to the king's father and was his friend - 'that is why he is also my child'.
Praising the king's statement on Friday calling for an end to the killings in Natal, Mr Mandela urged ANC supporters to respect the king. 'I was very happy His Majesty came out against violence,' he said.
After a meeting with clergy led by Archbishop Desmond Tutu of Cape Town, the king had appealed to his subjects 'of whatever political affiliation' to stop the killings. 'I plead to them now to take into their consideration the people killed in Natal / KwaZulu. This must come to an end . . .'
Mr Mandela said: 'I was happy he made a statement which befits one of the most illustrious royal houses.'
Whether the king's call will allow polling to go ahead 10 days from now in parts of Natal and KwaZulu dominated by the Inkatha Freedom Party is doubtful. The IFP, which is boycotting the election, is defying the state of emergency and calling for a week of protest marches, some provocatively close to ANC strongholds. Not to be outdone, ANC organisers in Natal are organising marches close to Inkatha areas. More than 200 people have died in the region since the state of emergency was declared in Natal on 31 March, and daily killings and clashes continue. In rural areas Inkatha supporters have told people to stay at home on polling days or be killed.
An estimate by a European Union election monitor that polling could go ahead in 65 per cent of Natal is thought too optimistic, even by other monitors. Pessimists say only about half the Natal voters will feel free to vote under present conditions.
At one level Mr Mandela's call for reverence for the king is part of a political ploy to flatter him and grant him constitutional ceremonial powers, in return for Goodwill's acceptance of the election and his support for peaceful polling. The king, who has said he will not vote, still has great weight among Zulus of whatever political persuasion, and if he was separated from Chief Buthelezi, the IFP and Zulu separatism, already weakened, would crumble.
But King Goodwill is not known to be an independent thinker and, surrounded by advisers loyal to his uncle, he has so far shown little sign of moving into the ANC camp.
The ANC's plan seems to be to divide the king from Chief Buthelezi, encourage the government to maintain a strong military presence during the election, then cut off official funding to the KwaZulu government. Chief Buthelezi gained substantial concessions during the early constitutional negotiations, but his opposition to the elections and the threat by Inkatha warlords to disrupt it have forced the ANC and the government to resist further concessions.
Last week's attempt at mediation by Henry Kissinger and Lord Carrington collapsed as soon as it started, because Chief Buthelezi insisted on postponing the elections, a step the government and the ANC refused even to put on the agenda. But Chief Buthelezi seems to have run out of options. Even former supporters, including the white press, are now abandoning him.
Talk of a 'Savimbi option' by Chief Buthelezi is unrealistic. If, like the Angolan politician, he opts for war after the election, he has no external support, and little weaponry or trained fighters. Yet 'Zulu-ness', once a symbol of the indomitable warrior nation, is still a potent force, although it is undergoing rapid transformation and redefinition.
Despite talk of Zulu nationhood, the tribe, which emerged in the early 19th century and created an empire by war, has rarely been united. It has a complicated legacy that leaves divided loyalties. A former ANC president, Albert Luthuli, spoke of his loyalty to the king. In the 1950s the ANC branch in Natal was practically autonomous. Today ANC supporters tend to be urbanised and are younger and better educated. Inkatha people tend to be rural or older and less well educated, and loyal to their local chiefs.
Mr Mandela's journey to Natal yesterday was a brave one. If Inkatha Zulus were to try to demonstrate their power, it would be on their home ground and at a Mandela rally. I saw only one person dressed in traditional Zulu costume yesterday and carrying a club, but in his other hand he carried a black briefcase. Under the state of emergency, the rallies yesterday were not strictly legal; there was no police presence at Umlazi and only one police car at Lamontville, a township where he stopped on the way. A cheering crowd shuffled along beside Mr Mandela's car while he stood waving, and shaking hands. As he passed four heavily armed, grim-faced white policemen, he held out his hands to them and said: 'Thank you, thank you for being here.' They blushed and grinned like schoolboys praised by the head. One Mandela supporter burst out: 'I don't believe this. He loves everyone, this man - even the police.'
At an election rally near Soweto yesterday, President F W de Klerk warned Chief Buthelezi to discipline his followers. He said a planned IFP march through Johannesburg tomorrow would not be tolerated.