Boxing Legend and Humanitarian Muhammad Ali Dead in Arizona at 74

Boxing legend Muhammad Ali, aka "The Greatest," one of the top sports figures of all time, died at age 74 at a Phoenix-area hospital on Friday night.

Ali was said to have died of complications from Parkinson's disease, from which he'd suffered since the 1990s. Following medical setbacks that put him the hospital in 2014 and 2015, Ali was rushed to a hospital on Tuesday with a respiratory illness. His family gathered as his condition worsened on Friday, and a spokesman later announced Ali's death.

His declining mental condition was thought to have been brought on by repeated head blows during his career. The condition robbed him of motor skills, reducing his gait to a shuffle in recent years and making it difficult for him to do simple tasks. But family and friends said his mental faculties remained sharp, at least at times. In December, he responded to statements by Republican presidential candidate Donald Trump, saying "We, as Muslims, have to stand up to those who use Islam to advance their own personal agenda. They have alienated many from learning about Islam."

Ali was born January 17, 1942, in Louisville, Kentucky, and from humble beginnings rose to become the world's best-known athlete. His speed and power were nearly unmatched in the ring, and he entertained fans and the public alike with his insight and wit.

He changed his name from Cassius Clay after joining the Nation of Islam in 1964. He later converted to Sunni Islam and became one of the religion's most famous global spokesmen.

Although he could be an extremely divisive figure — he was banned from boxing for three years after refusing to submit to the draft during the Vietnam War — Ali went on to help countless people with his charitable donations and advocacy for Parkinson's research and treatment. After he moved to Paradise Valley in 2015, he funded what's now called the Muhammad Ali Parkinson's Center at St. Joseph's Hospital in Phoenix. 

His funeral is planned to take place in Louisville, where Mayor Greg Fischer ordered flags lowered to half-staff. More details were expected to be released on Saturday morning.