For sale, the cornet that opened the wonderful world of Louis Armstrong

The battered cornet that launched the career of the legendary Louis Armstrong, when he was a 13-year-old in a New Orleans orphanage, is to be sold at auction.

To coincide with the centenary of his birth this year, Sotheby's is offering the European-made instrument, also a century old, on which Armstrong learned to play. The worn cornet, taped together in places, is expected to fetch up to £80,000 in the sale of jazz legends' photos and memorabilia, beginning on 1 October.

Shawn March, Sotheby's instrument specialist in Chicago, said: "Jazz just wouldn't be what it is now if it wasn't for Louis Armstrong. He absorbed everything and made it his own. We've had an overwhelming amount of interest."

Armstrong, known as Satchmo – short for Satchelmouth because of his face-splitting grin – was one of music's true revolutionaries. But his troubles with the law as a youngster secured his place in musical history. He was sent to the New Orleans Colored Waif's Home, a military-style correctional school, because he fired a pistol in the air to celebrate New Year's Eve. Armstrong had his first musical instruction from Peter Davis, the quiet but stern director of the home's music programme. He gave Armstrong a tambourine to play in the school band and the lad soon graduated to a bugle, to announce the day's routines, then took cornet lessons.

Born an outcast in 1901, Armstrong's birth certificate was stamped "nigger illegitimus", his grandparents were ex-slaves, and soon after his birth Armstrong senior left Louis's mother, who took to "selling fish", or prostitution. To supplement her paltry income, five-year-old Louis helped deliver coal to the notorious New Orleans Storyville brothels, where he heard the first jazz greats: Buddy Bolden, Kid Ory and King Joe Oliver.

The Marceau cornet was kept in Peter Davis's care at the Waif's Home to be used by other young musicians. Shortly before his death, Mr Davis, the cornet and Armstrong were reunited at the New Orleans Jazz Museum. George Finola, a young cornet player from Chicago, then purchased the instrument from the Davis family to protect it as an historic artefact and it stayed in the museum until his death.

Armstrong led a gruelling life, playing an average of 350 concerts a year. He was taken ill in 1971, but refused to cancel a gig a few months before he died, telling his doctor: "My whole life, my whole soul, my whole spirit is to blow that horn. I got to do it, doc."