Progressive rock movement began in Great Britain in the late sixties as an outgrowth of psychedelic and underground rock. It had emerged in the wake of the psychedelic boom of 1967 and marked the most dramatic shift, stylistically. Here are 10 albums recorded in late 60s that, in my opinion, contributed to the development of 'progressive rock' music.

June 1967 - release of "Sgt. Pepper's Lonely Hearts Club Band", one of the most influential album in rock & roll history. Its ability to break down traditional musical barriers is unquestionable.

August 1967 - Pink Floyd's first album "Piper at the Gates of Dawn" release, recorded at EMI Studios next door to the Beatles, who were working on "Sgt. Pepper's..". The album combined the innovative soundscapes of the group's avant-garde experimentation with the cream of Barrett's eccentric song craft.

November 1967 - Moody Blues broke from their mid 60's pop scene to a more ambitious hybrid of rock/orchestral pop and released "Days of Future Passed", recorded with the London Festival Orchestra. and contained the between-song strains of Dvorak, David Rose, and Alfred Newman. The concept was very original and influenced many others to follow.

March 1968 - The Nice, the pioneers of "classical rock" released "Thoughts of Emerlist Davjack". Their sound was built around Emerson's dense, rippling keyboards, classical influences mixed freely with John Coltrane, Dave Brubeck and Thelonious Monk playing styles.

June 1968 - Pink Floyd released their second album "A Saucerful of Secrets", which saw the group develop their space rock style. It contains the memorably mysterious "Set the Controls for the Heart of the Sun", more relaxed and less intense "Remember a Day" and "See-Saw". The finale track is Barrett's chilling sing-off "Jugband Blues".

August 1968 - release of Jethro Tull's first album "This Was". It combined Mick Abrahams' rolling blues guitar solos and Ian Anderson's distinctive, stylized voice. It became a major underground and the mainstream hit in the UK, eventually reaching the Top 10.

December 1968 - Procol Harum recorded their second album "Shine On Brightly" with "In Held Twas in I" one of the most ambitious single compositions at its era.

December 1968 - Soft Machine's "Volume 1", recorded in April during the concerts in the USA, finally got released. They were already among most popular psychedelic bands in the UK. Alongside Pink Floyd, they were co-headliners at a huge underground fund-raising event called "The 14 Hour Technicolor Dream" which took place on April 29th at Alexandra Palace. Originally released only in the USA, the album includes the shock values of unstructured composition, although many of their works are songs with good taste and craftsmanship.

April 1969 - Soft Machine release their second album. The music on Volume 2 was evolving into a distinctive brand jazz-rock. It contains their most intriguing and exciting performance, highlighted by Robert Wyatt's very English spoken/sung vocals.

October 1969 - King Crimson's "In the Court of the Crimson King", acclaimed as a masterpiece by both the British and American press, contains all the elements that characterize progressive's maturity: Fripp's complex chord progressions, expansive use of mellotron, intense compositional rigor, classical symphonic arrangements. On the top of that Pete Sinfield's apocalyptic lyrics gave the album another unique quality that captured the imagination of a hippie audience.

And this was truly a starting point of new, discrete rock sub-genre, so-called "progressive". The progressive movement proceeded in several different directions with some, like Renaissance, Curved Air, The Moody Blues and The Nice, looking to classical music for their inspiration while others like Genesis and Yes headed off towards their own grandiose rhythmic and lyrical visions. Pink Floyd, who'd been among the leading psychedelic bands, evolved into a progressive band following the departure of their songwriter and guitarist Syd Barret.

Open air festivals had become an increasing important part of the underground scene during the late sixties and early seventies. Pink Floyd had headlined the first free festival in London's Hyde Park in 1968. The Isle Of Wight festivals drew over 200,000 people in '69 to see Moody Blues, The Nice, Joe Cocker, The Who and King Crimson. Even a bigger crowd saw Jimi Hendrix, The Doors, Free, Jethro Tull, Taste, Ten Years After and Emerson Lake and Palmer the following year.

By the period 1970/1971, bands such as Yes, Jethro Tull, Emerson Lake and Palmer and Pink Floyd were the 'Progressive Rock' market leaders, but other bands, such as Genesis (who had yet to make their significant commercial breakthrough), Van Der Graaf Generator and Gentle Giant all commanded substantial fan followings. Behind them were many others, who, although they failed to match their more illustrious peers in the sales stakes, nonetheless were making significant contributions to the genre, such as Beggars Opera, Cressida, East of Eden, Spring, Atomic Rooster, Gracious, Gnidrolog, Rare Bird, to name a few.