Muhammad Ali was a professional boxer and activist from the United States. He is regarded as one of the most significant sports figures of the twentieth century, earning the moniker "The Greatest."

Cassius Marcellus Clay was born in Louisville, Kentucky on January 17, 1942. Cassius Marcellus Clay Sr. was his father's name.

Ali was introduced to boxing by Louisville police officer and boxing coach Joe E. Martin, who encountered the 12-year-old enraged because a thief had stolen his bicycle.

He informed the officer that he planned to "whup" the thief. Clay was advised by the officer to first learn how to box.

He then began working with trainer Fred Stoner, whom he credits with providing him with "real training," eventually shaping "my style, stamina, and system."

He converted to Islam after 1961. On February 25, 1964, at the age of 22, he won the world heavyweight championship by defeating Sonny Liston in a major upset.

During that year, he formally changed his name to Muhammad Ali after denouncing his birth name as a "slave name."

He remained free while appealing to the Supreme Court, where his conviction was overturned in 1971.

Ali's first affiliation as a Muslim was with Elijah Muhammad's Nation of Islam (NOI). He later repudiated the NOI and converted to Sunni Islam.