Boxing legend Muhammad Ali was reportedly related to a slave who forewarned Union troops of a Confederate trap, according to the Washington Post.

Ali, born Cassius Clay Jr.,­­ is the great-great-great-grandson of Archer Alexander, whose likeness was used for the slave portrayed in the Emancipation Memorial statue in Lincoln Park near Washington, D.C.

In 1863, Alexander journeyed five miles to alert the Union Army that Confederate soldiers demolished a bridge they planned to cross. He later fled to St. Louis in fear of the consequences of leaking information.

“Go for your freedom ef [sic] you dies for it,” the former slave famously said.

Keith Winstead, Ali’s third cousin, an amateur genealogist found the familial link using, a personal genomics and biotechnology company based in California. Through his research, Winstead discovered that Ali’s father, Cassius Clay Sr., was the son of Alexander’s great-granddaughter, Edith Greathouse.

Maryum Ali, the boxer’s oldest daughter, said, “He would have loved knowing he was connected to someone like that. He was ahead of people in understanding that there was a connection that went back through slavery to the kings and queens in Africa.”

The three-time heavyweight champion used his voice to fight against white oppression. Jonathan Eig, author of the biography, Ali: A Life, spoke about how pleased the legendary boxer would be if he knows about the discovery when he was alive. “The beautiful thing about Ali is that he acted all along as if he were royalty, that he had a claim to greatness.”

Eig continued, “Ali spent much of his life attacking racist ideas. If he had known that his great-great-great-grandfather was such a brave and intelligent man, surely would have strengthened his argument.”

Ali died in 2016 after a long battle with Parkison’s disease at the age of 74.