Guitarist Paul 'Bonehead' Arthurs, bass player Paul 'Guigsy' McGuigan and drummer Tony McCarroll originally formed as 061 (after the telephone area code for their home city of Manchester), then changed their name to The Rain.
Lacking direction - and decent songs - they sacked their original singer in favour of stroppy, loud-mouthed Liam Gallagher. Changing their name to Oasis they asked Liam's older brother, Noel (pictured at right), to join them.
A serious guitarist and budding tunesmith, Noel had been earning a living as technical roadie for local indie pop heroes Inspiral Carpets. He soon took control and hammered the band into shape by enforcing a strict rehearsal regime.
On 31 May 1993, Creation Records owner Alan McGee saw Oasis play at King Tut's Wah Wah Hut in Glasgow, Scotland (they were supporting Boyfriend, 18 Wheeler and Sister Lovers in case you were wondering) and was so impressed that he offered them a record deal on the spot.
They signed a six-album deal with Creation in October, with a £40,000 advance. By late 1994 their debut album Definitely Maybe had gone straight to the top of the UK charts.
The Gallagher's arrival was perfectly timed. A pair of mono-browed enforcers preaching the glories of The Beatles and The Sex Pistols, they crushed the opposition with their sledgehammer melodies, sung with brutalist zeal by 22-year-old-thug-Adonis Liam Gallagher.
Their first magazine cover christened Oasis "The Sex Beatles" and Gallagher Junior was quick to describe his vocal style as a blend of Johns Lennon and Lydon.
Original drummer Tony McCarroll was replaced in 1995 by Alan White, and in August of that year the duel between Oasis and Blur over whose single would enter the UK charts at Number One made the British national newspapers and TV news.
The rivalry between the two groups was often compared to that between The Beatles and The Rolling Stones, but in fact those '60s giants had a genial relationship and a gentleman's agreement not to release singles at the same time.
Blur and Oasis, however, appeared to loathe each other with a genuine and deep passion (Noel Gallagher shocked the pop community when he expressed the wish that Blur's singer and bassist would both "catch AIDS and die").
Underlying the verbal vendetta between the two bands was a regional antagonism. Blur came from the South of England and were middle-class, albeit infatuated with London proletarian lifestyles. Oasis - from the North of England - were the genuine working class article.
(What's The Story) Morning Glory (1995) was deeply indebted to The Beatles. Liam Gallagher sounded like a more nasal John Lennon, with the joie de vivre curdled to a sour arrogance.
Sonically, Oasis were basically a grungier version of The La's, an early '90s Beatles-obsessed outfit from the North of England.
While a fervent admirer of La's songwriter Lee Mavers, Noel Gallagher said that when he first saw that band perform, "I thought, 'he's ripping off my songs!'".
In truth, both songwriters were so chronically influenced by Lennon & McCartney that they were basically filling in the gaps in The Beatles songbook - and inevitably sometimes the same gap.
Theorist Joe Carducci used the term "genre mining" to describe such a classic-rock approach.
A marginally less hook-laden reprise of the debut LP Definitely Maybe, Morning Glory suggested Oasis' particular seam of sound was close to exhaustion and the band would subsequently take a great deal of flak both for their boorish antics and for dragging indie rock back into an era of retrograde conservatism. Even Noel Gallagher suggested in interviews that they were delivering diminishing returns with each new album.
But it's hard to deny the stone killer qualities of their debut album, recently voted the 'best album of all time' in an NME.com poll. Tracks like Cigarettes And Alcohol, dirty, restless and toxic, were about the everyday frustrations of a dead-end job and the need for kicks.
Wonderwall (1995) became the crossover Britpop anthem that broke Oasis into the mainstream, got voted Best Song of All Time by Virgin Radio in 2005, and entered rock legend - enduring on football terraces and in pub lock-ins across the nation.
By August 1996 - when the band broke UK attendance records playing two nights at Knebworth to over 500,000 people - What's The Story... had gone platinum nine times over, defining a time and place more absolutely than any other UK album released since.
But at the start of their eighth US tour the following month, Liam failed to join the band in Chicago in order to house-hunt in London with his serial-rockstar-dating girlfriend, actress Patsy Kensit. Explaining his no-show, he said he was indifferent to playing to "fucking yanks.
Oasis continued touring the songs that made them famous and dutifully made a new record every two or so years.
Paul "Bonehead" Arthurs
Paul "Guigsy" McGuigan