Half a century ago in upstate New York, a festival took place at a 600-acre dairy farm near White Lake in Bethel which completely transformed popular music.

The festival was Woodstock – and more than 500,000 of the flower-power generation flocked to it for three days from Friday August 15th to Sunday August 18th, 1969.

Thirty two acts, mainly from the USA, performed in the open air to an ecstatic reception that would become the stuff of folk legends.

But one of the biggest voices there was not an American at all. It belonged to a man brought up on the streets of Salford.

That man was Graham Nash, vocalist and guitarist of Manchester band the Hollies.

Graham Nash on a visit to BBC Radio 2, May 2016

Graham Nash on a visit to BBC Radio 2, May 2016

He had just formed a new vocal group with American singers David Crosby and Stephen Stills, along with Canadian artist Neil young.

The band was simply called Crosby, Stills, Nash and Young – or CSNY for short.

David Crosby, far right, and the Byrds being interviewed in the UK, August 1965

David Crosby, far right, and the Byrds being interviewed in the UK, August 1965

Song-writer and guitarist Crosby had split from the Byrds in 1967. Stills was a member of Buffalo Springfield, which collapsed in early 1968.

Nash came into the picture in July 1968 at a party at Joni Mitchell’s house. He sang an impromptu three-part harmony with Crosby and Stills – and the voices gelled.

Folk singer Joni Mitchell is welcomed to the UK by Graham Nash, December 1969

Folk singer Joni Mitchell is welcomed to the UK by Graham Nash, December 1969

Feeling creatively frustrated with the Hollies, Nash crossed the Atlantic to record the new group’s first album in May 1969. It was called Crosby, Stills and Nash.

Singer song-writer Young came onboard in August 1969. The four played their very first gig together on August 16th – the day before they were due to appear at Woodstock!

CSNY’s hour-long set at Woodstock was sandwiched between Blood, Sweat and Tears and the Paul Butterfield Blues Band at 3.00am on the Monday morning.

Stills announced on stage that he and the rest of the band were terrified as it was only their second gig. The actual language used on the day was a little more colourful!

Young skipped most of the acoustic part of the act, but it was still declared a success. The band’s profile was boosted by appearing in the Woodstock movie and Mitchell’s famous song about the festival.

Three hits came from the CSNY’s first album – Suite: Judy Blue Eyes and the singles Teach Your Children and Marrakesh Express, both written by Nash.

Ironically, Marrakesh Express, which reached No. 28 in the American charts, and Teach Your Children were both rejected by the Hollies.

The album Crosby, Stills and Nash peaked at No.6 in the charts, but had recorded triple platinum sales by 1999 and went quadruple platinum in 2001.

The band recorded a second album, Déjà vu, in 1970 and a third, CSN, in 1977. But relationships between the four singers were difficult and each pursued solo projects over the years.

One of the most famous of these was Young’s blockbuster album Harvest, released in February 1972. Nash sang on two of the tracks.

Canadian singer song-writer Neil Young at Wembley, April 1990

Canadian singer song-writer Neil Young at Wembley, April 1990

The single Heart of Gold rocketed to the top of the US charts and Harvest became the best-selling album of the year.

Nash’s own solo projects included collaborations with Crosby, which spawned the hit single Immigration Man, and co-founding the movement Musicians United for Safe Energy.

He briefly rejoined the Hollies in 1983 to mark their 20th anniversary and record the two albums What Goes Around and Reunion.

While Nash was enjoying success in the USA, the Manchester music scene continued to flourish in the late 1960s.

Groups like Herman’s Hermits, Wayne Fontana and the Mindbenders and Freddie and the Dreamers topped the American charts.

Manchester band Herman’s Hermits led by singer Peter Noone, centre, June 1966

Manchester band Herman’s Hermits led by singer Peter Noone, centre, June 1966

Wayne Fontana and the Mindbenders board a plane for their American tour, April 1965

Wayne Fontana and the Mindbenders board a plane for their American tour, April 1965

In one extraordinary week in May 1965, all three bands were at Nos. 1, 2 and 3 in the Billboard top 100.

In 1965, Herman’s Hermits even outsold the Beatles! The Manchester band sold more than 10 million records in seven months.

In the early 1970s, Manchester’s creative mantle passed to the Bee Gees, Barclay James Harvest and 10cc.

An early photo of Manchester group the Bee Gees, July 1968

An early photo of Manchester group the Bee Gees, July 1968

The city led the way for recording facilities too. Graham Gouldman and Eric Stewart of 10cc set up Strawberry Studios in Stockport, the first world class recording studio outside London.

In the same Stockport building, Keith Hopwood of Herman’s Hermits founded Pluto Studios which later moved to central Manchester.

The Hollies with Graham Nash, centre, and lead singer Allan Clarke, far left, June 1965

The Hollies with Graham Nash, centre, and lead singer Allan Clarke, far left, June 1965