President Donald Trump says he's considering a posthumous pardon for boxing's first black heavyweight champion more than 100 years after the late Jack Johnson was convicted by all-white jury of accompanying a white woman across state lines.

Trump announced Saturday on Twitter that the actor Sylvester Stallone, a friend of his, had called to bring Johnson's story to his attention.

"His trials and tribulations were great, his life complex and controversial," Trump wrote from his Mar-a-Lago club in Florida. "Others have looked at this over the years, most thought it would be done, but yes, I am considering a Full Pardon!"

Johnson is a legendary figure in boxing and crossed over into popular culture decades ago with biographies, dramas and documentaries following the civil rights era.

Most famously, his story was fictionalized for the play "The Great White Hope," starring James Earl Jones, which won the Pulitzer Prize for drama and the Tony Award for best play in 1969. A film version with Jones was released in 1970. More recently, the documentary "Unforgivable Blackness: The Rise and Fall of Jack Johnson," directed by Ken Burns, was aired on PBS in 2004.

Johnson was convicted in 1913 for violating the Mann Act, which made it illegal to transport women across state lines for "immoral" purposes.

The boxer died in 1946. His great-great niece has pressed Trump for a posthumous pardon, and Sen. John McCain, R-Ariz., and former Senate Majority Leader Harry Reid, D-Nev., have been pushing Johnson's case for years.

Stallone, who starred in the 1976 boxing film "Rocky" and several sequels, is a supporter of the president and attended Trump's New Years' Eve party at Mar-a-Lago in 2016.

In Jim Crow America, Johnson was one of the most despised African-American of his generation, humiliating white fighters and flaunting his affection for white women.

The son of former slaves, he defeated Tommy Burns for the heavyweight title in 1908 at a time when blacks and whites rarely entered the same ring. He then mowed down a series of "great white hopes," culminating in 1910 with the undefeated former champion, James J. Jeffries.

"He is one of the craftiest, cunningest boxers that ever stepped into the ring," said the legendary boxer John L. Sullivan, in the aftermath of what was called "the fight of the century."

After seven years as a fugitive following his conviction, Johnson eventually returned to the U.S. and turned himself in. He served about a year in federal prison and was released in 1921. He died in 1946 in an auto crash.

Posthumous pardons are rare, but not unprecedented. President Bill Clinton pardoned Henry O. Flipper, the first African-American officer to lead the Buffalo Soldiers of the 10th Cavalry Regiment during the Civil War; he was framed for embezzlement. Bush pardoned Charles Winters in 2008, an American volunteer in the Arab-Israeli War convicted of violating the U.S. Neutrality Acts in 1949.