Float like a butterfly, sting like a bee, simply the greatest... known as Ali.

Former world heavyweight boxing champion Muhammad Ali would have turned 77 today... but just under 30 months since he passed away on 3 June 2016 it's not his skill in the ring that's so greatly missed... it's all the other qualities and flaws that set him apart as a man.

One of the most famous boxers of all time, Ali was a master showman, an amazing athlete and a canny opponent, but he was also a man of principle, a humanitarian and a gentleman, who showed great humility when struck down by illness in later life.

There's no doubting Ali was a match for anyone in the ring... but the fact he's known as the "greatest" owes as much to his oratory as his pugilatory skills.

Outwardly, despite much adversity, two contrasting facets of his character shone through: his humour and his bravado.

His conversion to Islam and conviction for draft evasion surrounded him with controversy and exiled him from boxing for three years, but despite that hiatus the 'Louisville Lip' returned to the ring to become the first person in history to win the heavyweight title three times. But it wasn't that he did it that set him apart, it was how.

Ali's quick reflexes and strong punches made him a formidable fighter, but his quick wit and great confidence created the air of invincibility that won the world over.

Born Cassius Marcellus Clay Jr on 17 January 1942 in Louisville, Kentucky, to Cassius Clay Sr and Odessa Grady Clay, Ali also had a brother Rudy, two years his junior.

At the age of 12 he began learning to box after an incident at the Columbia Auditorium, where he'd gone with a friend to have some of the free hot dogs and popcorn available to visitors of the Louisville Home Show. When the boys were done eating, they went back to get their bikes only to discover Ali's had been stolen.

Furious, Ali went to the basement of the auditorium to report the crime to police officer Joe Martin, who was also a boxing coach at the Columbia Gym. When Ali said he wanted to beat up the person who stole his bike, Martin told him he should probably learn to fight first. A few days later, Ali began training at Martin's gym.

From the start Ali took his training seriously. On school days, he woke early so he could go running and then would workout at the gym in the evening. When Martin's gym closed at 8pm, Ali would then train at another boxing gym.

Over time, Ali began his own eating regimen that included milk and raw eggs for breakfast. Concerned about what he put in his body, he stayed away from junk food, alcohol and cigarettes.

Even in his early training, he boxed like no one else. He was fast... so fast he didn't duck punches like other boxers, instead he just leaned back away from them. He also didn't put his hands up to protect his face; he kept them down by his hips.

In 1960 the Olympic Games were held in Rome and Ali, then 18, had already won national tournaments such as the Golden Gloves and believed he was ready for the Olympics.

On 5 September 1960 he proved himself right, beating Poland's Zbigniew Pietrzyskowski by unanimous decision in the light-heavyweight division to claim Olympic gold.

After the Olympics Ali moved into the professional ranks and quickly realised there were things he could do to create attention for himself. For instance, before fights, he would say things to worry his opponents and frequently he declared: "I am the greatest of all time!"

His theatrics worked, with many paying to see his fights just to see him lose... but he didn't. In 1964, even heavyweight champion Charles "Sonny" Liston got caught up in the hype and agreed to fight Ali.

Unbeaten in 19 professional fights, winning 15 by knockout, Ali fought Liston for the heavyweight title in Miami, Florida, on 25 February. Liston tried for a quick knockout but found he couldn't catch Ali and by the seventh round he was exhausted, had hurt his shoulder, and was worried about a cut under his eye.

Liston refused to continue and Ali was proclaimed heavyweight champion of the world.

The following day Ali publicly announced his conversion to Islam, having joined Elijah Muhammad's Nation of Islam which advocated a separate black nation. Since many people found the Nation of Islam's beliefs racist, they were angry and disappointed Ali had joined them.

Up to this point, he had still been known as Cassius Clay but on joining the Nation of Islam he shed his "slave name" and became Muhammad Ali.

In the three years after the Liston fight, Ali won every bout. He had become one of the most popular athletes of the 1960s and a symbol of black pride. Then in 1967, Ali received a draft notice to the US Army.

Since Ali was a famous boxer he could have requested special treatment and just entertained the troops but his deep religious beliefs forbade killing, even in war, so Ali refused to go to Vietnam.

In June 1967 he was tried and found guilty of draft evasion, fined US$10,000 and sentenced to five years in jail. He remained out on bail while he appealed but as a result of the public outrage he was banned from boxing and stripped of his heavyweight title.

For three and a half years, he was "exiled" from the ring. While watching others claim the heavyweight title, he lectured around the country to earn a living.

By 1970 the American public had become disillusioned with the war and the anger against Ali was decreasing so he was allowed to return to the ring.

Following an exhibition bout on 2 September, Ali's comeback fight was against Jerry Quarry in Atlanta, Georgia, on 26 October. During the fight Ali appeared slower than before, but Quarry's manager threw in the towel ahead of the fourth round.

Ali was back and he wanted to reclaim his heavyweight title... on 8 March the following year he got his chance, when he was matched against Joe Frazier at Madison Square Garden in the "fight of the century".

Viewed in 35 countries around the world, Ali introduced his "rope-a-dope" technique with the goal being to quickly tire out Frazier.

Although Ali scored well in a few of the rounds, in many more he was pounded by Frazier. The fight went the full 15 rounds, with both fighters still standing at the end, and was unanimously awarded to Frazier. Ali had lost his first professional fight and had officially been dethroned.

But outside the ring he was a winner, his appeal against his draft evasion conviction had gone all the way up to the US Supreme Court and on 28 June 1971 they unanimously reversed the lower court's decision. Ali had been exonerated.

Three years later he had another crack at the heavyweight championship title, this time against George Foreman who had replaced Frazier as champion. On 30 October 1974 the pair met in the "rumble in the jungle".

A few months earlier Ali had won a rematch against Frazier but was much slower and older than he used to be and was not expected to have a chance against Foreman, who many considered unbeatable.

The bout was held in Kinshasa, Zaire, and once again Ali used his rope-a-dope strategy... enjoying much more success in the African heat. Ali was able to tire out Foreman so much that by the eighth round he knocked him out. Ali was back on top of the world.

Four defences later he was back in the ring with Frazier on 1 October 1975 in a fight dubbed "the thrilla in Manila".

Since their first outing in 1971 Ali's pre-fight antics had caused huge animosity between the pair, his comments greatly upsetting Frazier.

Held in Manila, Philippines, it was a brutal contest with both fighters determined to win. By the time the bell for the 15th round went Frazier's eyes were swollen nearly shut; his manager wouldn't let him continue. Ali won the fight, but he himself was badly hurt as well.

Following the Frazier fight Ali announced his retirement but it proved only temporary as it was all too easy to pick up a million dollars for one more bout. Six defences followed but Ali didn't take the fights too seriously and became lax on his training.

Then on 15 February 1978 Ali went one fight too far, losing his title to novice pro Leon Spinks, who had emulated Ali's light heavyweight gold at the 1976 Olympics. The fight did go 15 rounds, but Spinks dominated the contest and was a clear winner.

Ali was furious and wanted a rematch. Spinks obliged. While Ali worked diligently for their rematch, Spinks didn't, and although the fight went the full 15 rounds again, this time Ali was the obvious winner.

Once again he was on top of the world, but this time he'd become the first boxer in history to win the crown three times.

Ali fought two further fights, beating Larry Holmes to retain his title in 1980 but then lost to Trevor Berbick a year later, when he finally retired from the ring.

Ali had been crowned the world heavyweight champion on three separate occasions and won 56 bouts in his professional career, losing only five. Of the 56 wins, 37 were by knockout. Unfortunately it all had an impact on his body, especially the poundings he took as a result of his strategy against Foreman and Frazier, and in later life his speech became slurred and his hands started to shake. He suffered from over-tiredness and in September 1984 he was hospitalised to determine the cause. His doctors diagnosed Parkinson's Disease.

His condition worsened with time but it never prevented his humanitarianism from shining through as he continued to offer his services to help those less fortunate than himself. He worked tirelessly to help charities around the world and also spent a great deal of time signing autographs for his adoring fans.

When actor Michael J Fox announced he also suffered from Parkinson's in 1998, he and Ali joined forces to spread awareness about the critical need to fund research for a cure. They made a joint appearance before Congress to push the case in 2002.

As part of the campaign, the pair made a series of short videos to raise awareness and encourage the public to make donations to the Michael J Fox Foundation for Parkinson's Disease, a non-profit organisation founded by Fox in 2000.

Ali also undertook many goodwill missions to Afghanistan and North Korea, delivered medical supplies to an embargoed Cuba, and even travelled to Iraq to secure the release of 15 US hostages during the first Gulf War.

He also went to South Africa to meet Nelson Mandela upon his release from prison, an encounter the future president apparently found nerve-wracking.

"When I met Ali for the first time in 1990, I was extremely apprehensive," said Mandela in an interview. "I wanted to say so many things to him. He was an inspiration to me, even in prison, because I thought of his courage and his commitment to his sport. I was overwhelmed by his gentleness and his expressive eyes."

Ali married his fourth wife, Lonnie, in 1986. He had nine children, most of whom avoided the spotlight of which he was so accustomed. One of his daughters, however, Laila Ali, pursued a career as a professional boxer during which she went undefeated in 24 bouts between 1999 and 2007 while capturing a number of titles in various weight classes.

In 1996 Ali was chosen to light the Olympic flame at the start of the XXVI Olympiad in Atlanta, Georgia. The outpouring of goodwill that accompanied his appearance confirmed his status as one of the most-beloved athletes of all time.

Ali’s religious views had also evolved with time and he'd turned to Orthodox Islam, his earlier adherence to the teachings of Elijah Muhammad replaced by a spiritual embrace of all people and preparation for his own after-life.

After the 9/11 attacks on the World Trade Centre in 2001 Ali spoke out against Islamophobia and terrorism: "I am angry that the world sees a certain group of Islam followers who caused this destruction, but they are not real Muslims. They are racist fanatics who call themselves Muslims, permitting this murder of thousands."

The dramatic period of his life from 1964-74 was the subject of the film Ali (2001), in which he was portrayed by Will Smith. His life story is told in the documentary film I Am Ali (2014), which includes audio recordings that he made throughout his career and interviews with those close to him.

On 3 June 2016 he died aged 74 in Phoenix, Arizona, after suffering respiratory problems. He'll never be forgotten.

See Time's tribute to Muhammad Ali.