No jazz musician in the 20th century was more influential than Louis Armstrong who died on 6 July, 1971 aged 69.

Popularly known as “Satchmo” (short for satchel-mouth) he rose from poverty to become a cultural icon and the pre-eminent jazz musician of his generation.

With his virtuoso trumpet playing and guttural vocal style Armstrong made hit records for over half a century and did more than anyone to transform jazz from regional dance music into a recognised art form.

Widely held to be the inventor of the improvisatory form of “scat” singing, Mr Armstrong was a joyful and spirited entertainer who appeared in films and performed for heads of state. But most of all he was the father of jazz.

Louis Daniel Armstrong was born on 4 August, 1901 into extreme poverty in New Orleans . His father was a factory worker who abandoned the family shortly after Lous was born.

He showed an early interest in music and a junk-yard owner for whom he worked helped him to buy a cornet which he taught himself to play.

When he fired a gun into the air on New Year’s Eve, 1912, he was sent to a reform school – the New Orleans Home for Coloured Waifs – where he played cornet and bugle in the school band, eventually becoming its’ leader.

On his release Mr Armstrong worked as a labourer whilst trying to establish himself as a musician, eventually joining the Kid Ory Band where cornetist Joe “King” Oliver took him under his wing and became a surrogate father figure.

He joined Oliver’s Creole Jazz Band in Chicago in 1922 and made his first recordings as a second cornetist in that band in the spring of 1923. He moved to New York in 1924 to join the Fletcher Henderson Orchestra where he switched to the trumpet.

By 1925, he was back in Chicago and, contracted to OKeh Records made recordings with studio-only bands called the Hot Fives or the Hot Sevens – the Hot Fives’ “Muskrat Ramble” gave him a Top Ten hit in 1926.

He made his first Broadway appearance in 1929 and his recording of Fats Wallers’ “Ain’t Misbehavin” in the same year helped to set the stage for the popular acceptance of jazz that would follow.

By the 1930s Mr Armstrong was already a huge star and he would spend much of the next thirty years touring the world, first of all in big bands and when their popularity began to wane, in a six-piece band known as The All Stars.

Mr Armstrong was married four times, eventually settling with his last wife Lucille in a modest home in Queens , New York where he would often entertain the local community by playing the trumpet on the steps of his house.

His genial Southern personality and ability to bond with an audience became at least as well known as his music and at various times he was criticised by black activists of playing up to an “Uncle Tom” stereotype.

It is impossible to summarise the legacy of a true legend in a few words. His gravelly voice and unique and fearless musical improvisations will see “Satchmo” remembered as the greatest jazz musician ever.

25,000 mourners filed past his coffin as it lay in state. Afterwards, Dizzy Gillespie said: “Louis Armstrong's station in the history of jazz is unimpeachable. If it weren't for him, there wouldn't be any of us."