Muhammad Ali born Cassius Marcellus Clay Jr. (January 17, 1942 June 3, 2016) was an American professional boxer and activist. He is widely regarded as one of the most significant and celebrated sports figures of the 20th century. From early in his career, Ali was known as an inspiring, controversial, and polarizing figure both inside and outside the ring. Cassius Clay was born and raised in Louisville, Kentucky, and began training as an amateur boxer when he was 12 years old. At age 18, he won a gold medal in the light heavyweight division at the 1960 Summer Olympics in Rome and turned professional later that year. At age 22 in 1964, he won the WBA, WBC, and lineal heavyweight titles from Sonny Liston in a big upset. Clay then converted to Islam and changed his name from Cassius Clay, which he called his slave name, to Muhammad Ali. He set an example of racial pride for African Americans and resistance to white domination during the Civil Rights Movement.