His book Band of Brothers – which chronicled the exploits of one company of US airborne troops in second world war Europe – was turned into a highly praised TV series.

But now American historian Professor Stephen Ambrose, who was President Dwight D Eisenhower's official biographer and wrote or edited more than a dozen books about him, is embroiled in a posthumous controversy. It is alleged that he invented many meetings he claimed to have had with Eisenhower, and even fabricated entire interviews with him. The revelations have sent shock waves through the scholarly community in the United States.

The books written by Ambrose, who died in 2002, brought him popular acclaim, and director Steven Spielberg used him as a military adviser on his 1998 Oscar-winning film Saving Private Ryan. Band of Brothers became a cultural milestone when it was turned into a TV series on which Ambrose was a producer. It was hailed for educating an entire generation about the sacrifices of their forefathers. But it appears that Ambrose indulged in some sort of fantasy about the extent of his relationship with Eisenhower. In TV interviews, he claimed to have spent "hundreds and hundreds of hours" with the former president. He even once said he would spend two days a week working with Eisenhower in his office.

However, recently studied records of Eisenhower's meetings contradict the notion that the pair had any lengthy face-to-face contact. "I think five hours [in total] is a generous estimation of the actual time they spent together. I personally would push it back to less than two or three," said Tim Rives, deputy director of the Eisenhower Presidential Library in Abilene, Kansas.

The discovery came to light almost by accident. The museum had been planning an exhibition exploring the relationship between Ambrose and Eisenhower. Rives found that the records showed that Ambrose and Eisenhower had met only three times, and never alone. He found that on seven occasions when Ambrose had claimed in the footnotes to his book Supreme Commander to have met Eisenhower, his subject was either elsewhere in the country or holding meetings with other people at the time. In one example, Ambrose claimed to have had an interview with Eisenhower in Pennsylvania, when Eisenhower was in Kansas. "The whole story kind of unravelled from there. It was quite a surprise. We were not looking for it, so it sort of happened almost by accident," Rives said.

Given that the lives of former presidents are meticulously detailed by their staff, there is almost no chance Ambrose could have held interviews with Eisenhower that went unrecorded.

Later claims by Ambrose in other books to have interviewed Eisenhower lack specific dates or places, but were just footnoted as "Interview with DDE". However, the range of subjects Ambrose claimed to have discussed with Eisenhower increased to take in topics such as giving up smoking or the Vietnam war.

Rives believes there is no way that Ambrose could have discussed such a vast array of subjects in the tiny amount of time he actually spent with his subject. "I find that very doubtful. That should be something that would be a concern for scholars. It could cast doubt."

Ambrose claimed that Eisenhower asked him to be his biographer by ringing him out of the blue in 1964. But Rives found letters from Ambrose to Eisenhower introducing himself and then asking him to agree to Ambrose writing his biography. This is not the first scandal over Ambrose's work. In 2002 he was accused of plagiarism in his book The Wild Blue. His publisher issued an apology but Ambrose said he had merely failed to put some short passages taken from elsewhere in quotation marks.