Muhammad Ali 'vastly improved'

Cassius Clay, later to become known as Muhammad Ali, rose to prominence at the 1960 Olympic Games in Rome, where he claimed a boxing gold medal in the light heavyweight division.

Ali boldly predicted how many rounds it would take him to knock out British boxer Henry Cooper ahead of their bout in London in 1963. The fight was stopped in the fifth round as Cooper was bleeding heavily from a cut around his eye and Ali was declared the winner. Cooper died in May 2011.

Ali first became a world champion in 1964, when he was still known as Cassius Clay. He upset the odds to defeat reigning champion Sonny Liston, a result which prompted him to yell "I'm the greatest" at gathered reporters.

In 1974, Ali took part in one of the most famous world championship fights in the history of boxing. He took on reigning champion George Foreman in Zaire, in a fight which was dubbed the "Rumble in the Jungle." Ali emerged victorious after flooring Foreman in the eighth round.

Ali provided one of the iconic images of the 1996 Atlanta Olympics when he lit the Olympic flame to officially declare the Games open.

In addition to lighting the flame, Ali also received a replacement gold medal for the one he had won 36 years earlier. Ali tossed the original into the Ohio River after being refused entry to a restaurant.

• Former world heavyweight champion Muhammad Ali has pneumonia


• The illness was discovered quickly, Ali's spokesman says


• He is expected to be out of the hospital soon, the spokesman says


• Ali became heavyweight world champion for the first time in 1964

(CNN) -- Famed boxer Muhammad Ali has "vastly improved" after being hospitalized over the weekend with a mild case of pneumonia, his spokesman Bob Gunnell said.

"Ali's team of doctors hopes to discharge him soon," said Gunnell.

Ali, 72, was admitted to an undisclosed hospital on Saturday.

"The Ali family continues to request privacy and appreciates all of the prayers and well wishes," read a statement sent from Gunnell.

Ali was born Cassius Clay and won an Olympic gold medal as a light-heavyweight at 18.

In 1964, he became world heavyweight champion in an upset victory against then-champion Sonny Liston, according to Ali's official website.

Shortly thereafter, he changed his name to Muhammad Ali to reflect his conversion to Islam.

The boxer was also known for his protest against the Vietnam War and refusal to be drafted into service out of religious conviction.

He retired from boxing in 1981 and announced his diagnosis with Parkinson's disease three years later.

Ben Brumfield, Joe Sutton, Kevin Dotson and Mayra Cuevas contributed to this report.