As Howard J. Kittell gave President Trump a tour of Andrew Jackson’s Hermitage plantation in Nashville a couple of months ago, the two discussed the seventh president’s military career, his controversial marriage, his image as a “tough, go-get-’em kind of guy” and his determination to keep the young country unified.

The Civil War never came up.

So on Monday, as Kittell checked his phone while stopped at a red light on the way to work, he was surprised to read that Trump had wondered aloud in a radio interview why there was a Civil War — and that he tied it to Jackson.

“I mean, had Andrew Jackson been a little later, you wouldn’t have had the Civil War,” Trump said. “. . . And he was really angry that — he saw what was happening with regard to the Civil War. He said, ‘There’s no reason for this.’ ”

Kittell, the president of the Hermitage, was stunned. “I am glad that I was stopped at the moment,” he said.

For one thing, Jackson was long dead by the time the Civil War happened. For another, he is not generally viewed as having had a direct role in the conflict.

Many presidents fancy themselves amateur historians who are fascinated by the office and how others have approached the job, often deeply researching and studying leaders they want to emulate — or to avoid emulating.

Trump, who reads sparsely, is not one of the history-buff types. But now that he is living in the museum-like White House, the president is learning — and sometimes mislearning — about the men in the oil paintings that fill his new home. His comments about those who have come before seem to reveal how little history he knew before taking office, and they often confound historians attempting to discern the lessons he is taking away from his predecessors’ time in office.

“Great president. Most people don’t even know he was a Republican, right?” Trump said of Abraham Lincoln during the National Republican Congressional Committee Dinner in March, referring to arguably the most famous Republican. “Does anyone know? Lot of people don’t know that.”

[‘Donald Trump’s Civil War,’ by Ken Burns]

Trump has said he looked to presidents Ronald Reagan and John F. Kennedy for inspiration for his inaugural address, yet his remarks on that day were far from Kennedy’s call for selfless devotion or Reagan’s sunny optimism; instead he decried “American carnage.” Trump has also repeatedly claimed to have had the largest electoral college victory since Reagan — even though Barack Obama had larger victories in both 2008 and 2012, as did Republican George H.W. Bush in 1988 and Bill Clinton in 1992 and 1996.

Trump takes a tour of the Hermitage on March 15. (Evan Vucci/AP)

Trump has increasingly cited past presidents as he ruminates about his new job, but he often gets facts wrong or comes up with interpretations sharply at odds with the historical consensus. Either way, he appears to revel in the sense of being a part of U.S. history.

One week into his presidency, Trump gave Sean Hannity of Fox News a tour of the Oval Office, listing the presidents featured — Thomas Jefferson, George Washington, “the great Abraham Lincoln” and Jackson — but spending more time marveling at his phone and the papers piled on his desk. At one point, Hannity asked why Trump was reusing Reagan’s Oval Office rug.

“First of all, I liked it,” Trump said. “I liked the look, I like the lightness, and I like having it be Reagan. I like Reagan. I disagreed with him on some things, primarily trade — he was not as strong on trade as I felt he should have been, but that’s okay. But he represented us very well.”

“In your lifetime, who was the president that maybe you admire the most?” Hannity asked.

“Well, I like Reagan,” Trump said. “I didn’t like him on trade but other than trade, I liked him very much. And he was okay on trade, but not great.”

A month later, Trump gave the hosts of Fox News’s “Fox & Friends” a similar tour and pointed out the portrait of Jackson. Trump’s chief strategist, former Breitbart editor Stephen K. Bannon, has pushed the comparison with Jackson, viewing the two as populists driving a political movement.

[Opinions: ‘Why was there a Civil War?’ Here is your answer]

“They say that his campaign and his whole thing was most like mine. That was interesting,” Trump said. “He was a great president — but a controversial president.”

Presidents often like to compare themselves to a predecessor. For Obama, it was Lincoln. For Bill Clinton, John F. Kennedy. For Reagan, Calvin Coolidge.

“They see as they wish to be seen,” said Jon Meacham, a presidential historian who has written about several presidents, including a Pulitzer Prize-winning biography of Jackson. “If you look at how presidents talk about their predecessors, almost invariably, it’s to highlight a trait they want us to see in themselves.”

Meacham interviewed Trump on three occasions last year for a July Time magazine article that explored how the candidate got his information. Trump mentioned Reagan but no other presidents, despite Meacham’s prodding.

When asked to name historical works that have left an impression, Trump instead told Meacham about his fascination with the Civil War — and claimed he once canceled a golf match to watch a PBS marathon of Ken Burns’s Civil War documentary.

“I think that anything having to do with the Civil War has always been very interesting to me, much more so than even the founding of the country,” Trump said in the interview. “It always seemed like something that could have been settled without the bloodshed. . . . I always felt that the South overplayed their hand.”

To Meacham, Trump’s fascination with the Civil War long predates his fascination with Jackson — and it seems to be the starting line from which he navigates through history. “The Civil War, to him, is the ultimate deal,” Meacham said.

When Trump ventured to Jackson’s Hermitage in March, Meacham — who lives in Nashville — wrote the president an open letter that highlighted how Jackson, despite his populist bent and harsh rhetoric, was determined to keep the country united.

Kittell said that Trump arrived at the Hermitage well versed in the controversies surrounding Jackson, who supported slavery and forced Native Americans off their lands with the Indian Removal Act of 1830.

“He’s a pretty complicated guy. He lived in a complicated time,” Kittell said.

[Donald Trump’s totally bizarre claim about avoiding the Civil War]

The president brought along a speech that highlighted Jackson’s upbringing, military career and approach to the presidency. Kittell also noticed that the president added asides that showed his familiarity with the material.

“It was during the Revolution that Jackson first confronted and defied an arrogant elite. Does that sound familiar to you?” Trump said in the speech, as the crowd laughed. “I wonder why they keep talking about Trump and Jackson, Jackson and Trump. Oh, I know the feeling, Andrew.”

Kittell thinks he knows what the president was trying to say earlier this week in his bungled comment on the Civil War. Jackson was fiercely opposed to division within the country and went to great lengths to keep South Carolina from seceding during the Nullification Crisis of 1832-1833. So if Jackson acted that way then, perhaps he would have also gone to great lengths to keep the Civil War from happening — although Kittell quickly notes that you get onto “pretty thin ice” when you start projecting how presidents might have acted or responded.

And, of course, the question remains: What about slavery?

White House officials have embraced interpretations like Kittell’s, without touching on slavery.

But the comment alarmed Rep. Tom Cole (R-Okla.), a member of the Chickasaw Nation, who said on MSNBC’s “Morning Joe” on Tuesday that he takes great offense to “anything nice said about Andrew Jackson.”

“That’s the one that concerns me the most,” Cole said. “My great-grandfather was forcibly removed out of — .”

Host Joe Scarborough cut Cole off, saying he was more concerned about Trump’s comments about North Korea, about the news of the day. A spokeswoman for Cole has yet to respond to a request for the congressman to finish his sentence about his family’s painful history.