U.S. President Donald Trump is seeking to take credit for making Juneteenth -- a day commemorating the end of slavery in the United States -- "very famous," after rescheduling his first rally since the start of the pandemic to avoid further criticism for seeming to co-opt it.

Trump told The Wall Street Journal that "nobody had ever heard of" the holiday before he brought it up.

"I did something good: I made Juneteenth very famous," Trump said in reference to the rally date in an interview published Thursday. "It's actually an important event, an important time. But nobody had ever heard of it."

The President was originally scheduled to hold his first political rally since the start of the coronavirus pandemic on Juneteenth, but eventually pushed the event back a day, to June 20.

Juneteenth is the oldest regular U.S. celebration of the end of slavery. It commemorates June 19, 1865: the day that Union Army Maj. Gen. Gordon Granger rode into Galveston, Texas, and told a group of enslaved African-Americans that the Civil War had ended and they had been freed. That event took place more than two years after President Abraham Lincoln signed the Emancipation Proclamation. Trump's rally was scheduled to take place on the holiday in Tulsa, Oklahoma: the site of a race riot 99 years ago, during which Black Wall Street in Tulsa's Greenwood neighborhood was burned down.

The comments come as Trump serves as president for a nation whose population continues to protest police violence and systematic racism after George Floyd's death at the hands of Minneapolis police officers in May.

In the wake of Floyd's death and the widespread protests over racial inequality, major companies have made Juneteenth a paid holiday, and state and federal legislators have brought more attention to it, as well. Forty-seven states and the District of Columbia mark June 19 as a state holiday or observance, but it still isn't a federal holiday.

Trump, who has few African-American advisers in the White House and in his Cabinet, told the Journal he "polled many people around him, none of whom had heard of Juneteenth."

But, according to the report, the President also asked an aide during the interview whether she had heard of the holiday "and she pointed out that the White House had issued a statement last year commemorating the day."

Trump didn't seem to know that his White House had been putting out public statements commemorating the day throughout his tenure in office.

"Oh, really? We put out a statement? The Trump White House put out a statement?" Trump said, adding that that was "good."

Trump also told the Journal that it was a black Secret Service agent who told him the meaning of Juneteenth.

Some critics -- including California Democratic Sen. Kamala Harris -- saw Trump's original Juneteenth rally as a racist play to "welcome home" white supremacists, but the President has said that he didn't schedule his rally on the holiday "on purpose."

When the rally was still schedule to take place on the holiday, Trump told Fox News: "The fact that I'm having a rally on that day -- you can really think about that very positively as a celebration. Because a rally to me is a celebration.

"It's an interesting date. It wasn't done for that reason, but it's an interesting date."

CNN's Harmeet Kaur and Jason Hoffman contributed to this report.