Progressive rock was born from a variety of musical influences in the late 1960s. An important precursor, Beck’s Bolero, composed by then-Yardbirds Jeff Beck and Jimmy Page in 1966, is a brief reworking of Maurice Ravel’s “Bol-ro”.

Bands such as The Nice and the Moody Blues began deliberately combining rock music with classical music, producing longer pieces with deliberate structures. German electronic music pioneers Tangerine Dream introduced a variety of synthesisers, tape effects, and other unusual sounds in their compositions, usually in purely instrumental albums. By the mid- to late-’60s, The Who had also created concept albums and rock operas, as well as long live rock song performances – although those were often in the more blues-based improvisational style also featured by contemporaries Cream and Led Zeppelin.

All of these bands are sometimes considered “early progressive,” or as part of a transitional genre between psychedelic and progressive sometimes referred to as proto-prog.

Key early progressive rock bands included The Nice and Soft Machine and the roots of the genre can be traced back to the mid-sixties. However, King Crimson’s appearance in February 1969 is often seen as a pivotal moment. King Crimson were quickly followed by other English progressive rock bands, including Yes, Genesis, Pink Floyd, Emerson Lake and Palmer (ELP), and Jethro Tull. Pink Floyds change in sound was probably due to the loss of Syd Barrett, their main song writer from 1965-1967. As for ELP, they inherited their singer and bassist, Greg Lake, from the original King Crimson lineup.

Progressive rock also gained momentum when many rock fans grew disillusioned with the “Peace and Love” movement. Progressive rock often distanced itself from the “smiles and sunshine” of 1960s pop music and moved towards darker and sometimes more violent themes. For example, Genesis’ Trespass includes “The Knife”, a song about a violent demagogue, and “Stagnation”, a song about a survivor of a nuclear attack. Genesis labelmates, Van der Graaf Generator, often took an existentialist approach that bordered on nihilism, even in album titles, such as Godbluff.

Progressive rock was especially popular in continental Europe and some parts of Latin America. Indeed, progressive rock enjoyed a captivating popularity in countries such as Italy and France. Germany also had a significant progressive movement, often referred to as Krautrock. The Italian progressive rock has been considered somehow a case of its own (sometimes cited as a separated genre, as “Italian symphonic rock”): although most of the bands scored appalling success even in their home country (often releasing only one LP), today CDs of otherwise unknown groups like Museo Rosenbach, Osanna, Il Balletto di Bronzo, Semiramis etc., along with the more renowned ones, are increasingly sought by fans as true classics of the genre, and also attracting the interests of higher musical critics and universities. In Brazil, Os Mutantes combined elements of traditional Brazilian music, psychedelic rock and experimental sounds to create intricate yet unorthodox arrangements, with imagery and lyrics inspired by fantasy, literature and history.

A strong element of avant-garde and counter-culture has long been associated with a great deal of progressive rock. In the 70’s, Chris Cutler of Henry Cow formed a loose collective of artists referred to as Rock in Opposition or RIO, whose purpose was essentially to make a statement against the music industry. The original members included such diverse groups as Henry Cow, Samla Mammas Manna, Univers Zero, Etron Fou Leloublan, Stormy Six, and later Art Zoyd, Art Bears, and Aqsak Maboul. The Rock in Opposition movement was short-lived, but the artists came to be recognized as some of the originators of Avant-progressive rock. Dark melodies, angular progressions, dissonance, free-form playing, and a disregard for conventional structure are all elements that have been used to describe these artists.

Progressive rock’s popularity peaked in the mid-1970s, when prog artists regularly topped readers’ votes in mainstream popular music magazines in England and America. By this time, several New World progressive rock bands had been formed. Toronto’s Rush were equally successful, with a string of hit albums extending from the mid-1970s to the present (though little of their recent work falls into the progressive rock category). Less commercially successful, but at least as influential as either band, were the Dixie Dregs, from Georgia (arguably more of a fusion band).