JOHANNESBURG » Sello Hatang pulled open a long yellow drawer and grabbed a cream-colored parchment. It declared Nelson Mandela an honorary citizen of Washington state.

Underneath was a similar one from Wisconsin and, below that, a key to the city of Chicago. In the dozens of other drawers lining the room were similar documents from around the world, and above them shelves full of gifts from foreign dignitaries, crystal award statues and shiny bronze figurines.

This is ground zero in the effort to maintain and shape the legacy of Nelson Mandela – widely referred to here as Madiba, his clan name – and to make sure that the narrative of the struggle does not deviate too much from what Mandela wanted it to be. It was also the site chosen on Saturday for the meeting between President Barack Obama and members of Mandela’s family.

"Everyone has an agenda, so we have an agenda too," Hatang, the chief executive of the nonprofit Nelson Mandela Center of Memory, said Friday afternoon. "But we want to be seen as trusted brokers. We want to keep the record accurate and to maintain Madiba’s papers and possessions in a place that both the public and scholars can access them and keep the historical record pure."

Hatang slid the drawer shut and walked across to a thick steel door. "This is the holy of holies," he said, spinning the wheel that unlocked the vault-within-a-vault.

He picked up a square, navy blue box about the size of a cigarette pack, opened it and handed over a palm-size bronze disc. It was Mandela’s Nobel Peace Prize.

A few feet away, atop a line of filing cabinets, was the first passport Mandela was allowed to have by the apartheid government and, beside it, a half-torn black-and-white photograph in a clear plastic sheath. It showed about 50 young black men in dark dress jackets posed in front of their rundown secondary school in the rural Eastern Cape. The tall young man in the back row, on the right, a serious but amiable expression on his face, is the teenage Nelson Mandela. It is the earliest known photograph of him.

Beside this is Mandela’s own desk calendar, on which he wrote such daily minutiae as how much money he had in his pocket, or his weight and blood pressure. There is the thick composition book in which he wrote his letters – every line is used on every page and the penmanship is painstakingly neat.

Hatang retrieved the Nobel medal and placed it back in its box, embossed with the initials "NM." He opened another folder beside it and pulled out the actual Nobel Prize proclamation. The penmanship on it was only marginally neater than Mandela’s own.

Soon, much of this material will be on display upstairs in the grand rooms that will be opened to the public in September or October. Already, there are displays there of books sent to Mandela and autographed by the authors, including Bill Clinton and Muhammad Ali.

The center sits behind tall walls on a busy street beside a roaring expressway, a short drive from the home where Mandela moved in this upscale neighborhood after his release from 27 years of imprisonment. It was here, as well, that Mandela kept his office after he stepped down from the South African presidency in 1999.

While this is the most prominent institution dedicated to Mandela’s legacy, it is not the only one. There is a Nelson Mandela Museum down in Mtatha, in the Eastern Cape, and a Mandela House museum in Soweto built around the house where he lived before his imprisonment.

With the 94-year-old Mandela in a Pretoria hospital, in what the South African government acknowledges are the final days of his life, Hatang said that those close to him are well aware that many will step forward to claim a piece of his legacy, or to try to shape his life story in ways that benefit their own interests.

"We cannot allow the past to be used as an instrument to advance someone’s interests," he said.

Already, everything in Mandela’s papers has been digitized, and about 15 percent of it is already online and searchable. The remainder will show up online slowly in coming months.

The center was constructed in 2002, officially dedicated by Mandela in 2004, then rededicated last year. It will be dedicated yet again when it opens to the public. "We have had a lot of dedications," Hatang said.

The center also keeps track of every tribute that Mandela has received around the world, all of it searchable on the center’s website.

A small town near Rome, population 900, has been named Mandela, and there is a Mandela Bridge in the Netherlands, a Mandela Close in Norwich, England, a Mandela Square in Kinshasa, Zaire, and a Mandela Park in Montreal. There is a Cafe Mandela in Copenhagen and a Madiba restaurant in Brooklyn.

A new species of spider, first found in the Drakensberg Mountains of South Africa’s Natal province, is called Singafrotypa mandela. A new type of orchid was named for him in Singapore, paravanda Nelson Mandela. And marine biologists decided to name a new type of sea slug the Mandelia Micocornata.

The greatest task of the center, Hatang said, is to keep his story alive for the younger generation of South Africans born after Mandela’s rise to power, known here as "Born Frees."

"There is a sense of alienation that is felt by the Born Frees," he said. "We want to create a dialogue with the Born Frees to ensure that there is some kind of understanding."

Many of these young people are mired in poverty and unemployment, and are not as enamored with the heroic saga of the anti-apartheid struggle as they might be. "This inequality breeds suspicions of the system," Hatang said.

"And then there will be the generation that comes after, those who are to be born in the years when Mr. Mandela is only a historical figure," he said.

So far, there is no name for them.

© 2013 The New York Times Company