<P> In 1968 Gram Parsons recorded Safe at Home with the International Submarine Band, arguably the first true country rock album . Later that year he joined the Byrds for Sweetheart of the Rodeo (1968), generally considered one of the most influential recordings in the genre . The Byrds continued in the same vein, but Parsons left to be joined by another ex-Byrds member Chris Hillman in forming The Flying Burrito Brothers who helped establish the respectability and parameters of the genre, before Parsons departed to pursue a solo career . Country rock was particularly popular in the Californian music scene, where it was adopted by bands including Hearts and Flowers, Poco and Riders of the Purple Sage, the Beau Brummels and the Nitty Gritty Dirt Band . A number of performers also enjoyed a renaissance by adopting country sounds, including: the Everly Brothers; one - time teen idol Ricky Nelson who became the frontman for the Stone Canyon Band; former Monkee Mike Nesmith who formed the First National Band; and Neil Young . The Dillards were, unusually, a country act, who moved towards rock music . The greatest commercial success for country rock came in the 1970s, with artist including the Doobie Brothers, Emmylou Harris, Linda Ronstadt and the Eagles (made up of members of the Burritos, Poco and Stone Canyon Band), who emerged as one of the most successful rock acts of all time, producing albums that included Hotel California (1976). </P> <P> The founders of Southern rock are usually thought to be the Allman Brothers Band, who developed a distinctive sound, largely derived from blues rock, but incorporating elements of boogie, soul, and country in the early 1970s . The most successful act to follow them were Lynyrd Skynyrd, who helped establish the "Good ol' boy" image of the subgenre and the general shape of 1970s guitar rock . Their successors included the fusion / progressive instrumentalists Dixie Dregs, the more country - influenced Outlaws, jazz - leaning Wet Willie and (incorporating elements of R&B and gospel) the Ozark Mountain Daredevils . After the loss of original members of the Allmans and Lynyrd Skynyrd, the genre began to fade in popularity in the late 1970s, but was sustained the 1980s with acts like . 38 Special, Molly Hatchet and The Marshall Tucker Band . </P> <P> Progressive rock, sometimes used interchangeably with art rock, was an attempt to move beyond established musical formulas by experimenting with different instruments, song types, and forms . From the mid-1960s The Left Banke, The Beatles, The Rolling Stones and The Beach Boys, had pioneered the inclusion of harpsichords, wind and string sections on their recordings to produce a form of Baroque rock and can be heard in singles like Procol Harum's "A Whiter Shade of Pale" (1967), with its Bach inspired introduction . The Moody Blues used a full orchestra on their album Days of Future Passed (1967) and subsequently created orchestral sounds with synthesisers . Classical orchestration, keyboards and synthesisers were a frequent edition to the established rock format of guitars, bass and drums in subsequent progressive rock . </P> <P> Instrumentals were common, while songs with lyrics were sometimes conceptual, abstract, or based in fantasy and science fiction . The Pretty Things' SF Sorrow (1968) and The Who's Tommy (1969) introduced the format of rock operas and opened the door to "concept albums, usually telling an epic story or tackling a grand overarching theme ." King Crimson's 1969 début album, In the Court of the Crimson King, which mixed powerful guitar riffs and mellotron, with jazz and symphonic music, is often taken as the key recording in progressive rock, helping the widespread adoption of the genre in the early 1970s among existing blues rock and psychedelic bands, as well as newly formed acts . </P>

How did the folk music and rock n roll of the 1960s express the mood of the counterculture