They are bitter political rivals today, but GOP front-runner Donald Trump once donated thousands of dollars to the Rev. Al Sharpton's National Youth Movement and did personal favors for him, National Review reports. The pair's relationship appears to have begun in the late 1980s when Trump was trying to increase interest in his Atlantic City businesses. The two were introduced by boxing promoter Don King."I wanted Sharpton to meet this guy because he was a giant in the business community and a giant in the human community," King told National Review. "Trump was a white ally — and he was one of distinction and renown in the business world."The website quoted a source close to Sharpton as saying that Trump gave Sharpton "anywhere between $20,000 and $150,000" for his National Youth Movement, which became the National Action Network, and for his activism.He also helped Sharpton's mistress get into an apartment she wouldn't have qualified for based on her income, another source said."Donald didn’t own this building," the source said. "But Sharpton asked if he could get his 'friend,' who didn’t have credit standards, into the building. Donald accommodated."Sharpton told National Review he never received any financial support from Trump, though other sources said Trump continued helping Sharpton even through the Tawana Brawley case and a 67-count indictment that he used his organization's funding for personal use."I don’t think we were close," Sharpton said. "We were relational."But National Review quotes a 2004 article in The Guardian in which Sharpton, then running for president himself, said he considered singer James Brown a mentor "alongside other prominent figures such as lawyer Johnny Cochran and Donald Trump, as a political supporter."Trump's office declined to comment for the story, National Review reported. But Mediaite noted that Trump addressed his relationship with Sharpton during a Fox News interview in December."I know [Sharpton] very well, and I’ve always gotten along with him, to be honest with you," he said. "There are those who say [Sharpton] likes Trump a lot. . . . Al’s a con man. He knows it. I know it. Don King knows it, his friend, who I go to with fights with — with Al. And they all know it."Sharpton feels it's the other way around, according to one National Review source."This guy is either playing the Right or playing us, whatever worked for him," the source said. "And Sharpton felt it was very cynical and was personally offended that [Trump] would be so cavalier."