? ca. 3000 B.C. Stonehenge built.
? 1937 J.R.R. Tolkien pens The Hobbit, inspiring Yes, Coheed and Cambria, and others.
? 1964 Bob Moog introduces the Moog synthesizer.
? 1966 Frank Zappa’s Mothers of Invention record the double album Freak Out!, an early prog inspiration.
? 1967 Love’s Da Capo becomes the first rock album to feature a side-long track, the 19-minute ”Revelation.”
? 1967 Procol Harum’s ”A Whiter Shade of Pale” — based on a Bach motif — hits the top 10.
? 1967 London ”happening” Fourteen Hour Technicolour Dream features Soft Machine and headliners Pink Floyd.
? 1969 King Crimson’s In the Court of the Crimson King takes rock to pretentious new heights.
? 1969 Deep Purple keyboardist Jon Lord presents his concerto for rock band and symphony orchestra at London’s Royal Albert Hall.
? 1971 Led Zeppelin’s eight-minute opus ”Stairway to Heaven” puts a bustle in prog’s hedgerow.
? 1973 Emerson, Lake & Palmer’s Brain Salad Surgery introduces the concept of ”Karn Evil.”
? 1973 Yes release Tales From Topographic Oceans, a dense double album that separates the diehards from the dabblers.
? 1973 Dungeons & Dragons debuts.
? 1975 Queen’s ”Bohemian Rhapsody” brings opera (and humor) into the mix.
? 1981 Rush’s Moving Pictures moves prog into the Reagan era.
? 1982 The film version of Pink Floyd’s The Wall is released.
? 1983 Prog cult faves Marillion release first album, Script for a Jester’s Tear.
? 1991 Long Island’s Dream Theater breathe new life into the genre with Images & Words.
? 1993 Tool’s Undertow introduces alt-rockers to prog.
? 1995 L.A.’s ProgFest lives long and prospers: After two years, it hits its stride with acts like Spock’s Beard and Solaris.
? 1997 Radiohead stuns fans of ”Creep” with bombastic opus OK Computer.
? 2001 System of a Down’s Toxicity kicks off the new-prog movement.