Donald Trump has enthusiastically agreed with a public assessment by a man he met while golfing that the “overwhelming difference” between the current US president and historical figures who incited fear – such as Attila the Hun, Genghis Khan, Napoleon, Stalin, Mao and Hitler – is that Trump is more powerful.

The US president reposted a short text in the early hours of Friday morning, in which the author writes:

“Historically, powerful people were characterised by brutal conquest and the fear that they instilled in the populations that came under their influence. Common names that would come to mind are Alexander the Great, the Caesars, Genghis Khan, Attila the Hunt, Tamburlaine, Napoleon and, more recently, Hitler, Mao, and Stalin.

“The overwhelming difference between each of the above when compared with President Trump is their lack of global reach.”

“Sounds good to me!” Trump wrote, naming the author as “presidential historian Dave King”.

King is not, in fact, a historian, but a Scottish-born businessman now living in South Africa who was previously the chair of the Rangers Football Club, based in Glasgow, which competes in the Scottish Premiership.

Trump seems to have first encountered him when King was caddying for his friend Gary Player, the Hall of Fame golfer, who was participating at an event in his honor.

CNN reported on Friday that Trump first mentioned the document in a March interview with the New York Times reporters Maggie Haberman and Jonathan Swan for their book Regime Change, an account of the first 14 months of Trump’s second term, which is to be published next week.

When the reporters asked Trump to describe the power he wields and his place in world history, according to CNN, Trump called for aides to bring him a two-page document he had received from someone he described as “a historian”.

Brandishing this document, Haberman and Swan reportedly write, Trump recited “the names of some of history’s most powerful figures, explaining how each fell short of his own power as US president”.

The leaders “maintained power through fear”, Trump reportedly said. “Who would ever do a thing like that? Right?”

CNN said Haberman and Swan eventually identified the “historian” in question as King, who told them he “had first shared his assessment of Trump’s power with Player and later explained it directly to Trump over golf in Florida”.

The book is based on more than 1,000 interviews over a three-year period. A review published by the Times on Friday notes comments Trump made during the same interview when he was asked to reflect on his legal battles and presidential campaigns.

“Essentially I won every fucking time,” Trump reportedly said. “And I’m tired of winning and winning and winning and just getting bad fucking press. It’s about time that you tell the truth. Okay?”

According to the New York Times, the two journalists report that Trump also said he considered making Florida’s governor, Ron DeSantis, who had been a rival nominee for president, his secretary of defense. “We need plot twists,” Trump reportedly told a “startled ally”.

And the Times added that the president reportedly also said at a high-level Oval Office meeting that “I’m not a big fan of Ukraine … except their women. They keep winning Miss Universe.”

Elsewhere in the book, according to CNN, the authors write that the White House press secretary, Karoline Leavitt, found Trump in the Oval Office “clutching a tube of superglue and attempting to affix gold decorations to the marble fireplace mantel”.

The book also reportedly recounts that Trump chose to make the former Federal Reserve chair Jerome Powell’s life miserable instead of firing him, and decided to do so by focusing on the cost of renovations to the Federal Reserve building.

“I want to bust his fucking balls, honestly,” Trump said of Powell during a meeting last year. “What about that fucking building? Can we stop it? Can we stop construction. I just want to bust his fucking balls. Fuck him.”

Trump’s pleasure at being compared to dictators follows on years of comments he has made about his admiration for autocrats and strongmen such as Vladimir Putin and Kim Jong-un.