With all respect, Rank Outsider, mentioning Bon Jovi & hard rock in the same sentence may not be that natural.
Like some posters before me, I´d say we have to define hard rock. What was invented, and how long did it live? Iron Maiden is the baby of Thin Lizzy. After Purple came... Nuthin. DP reinvented hard rock in 1984-86 while reunioning, and again in the 90´s. A Purple without Blackmore, or Gillan, or (worst of all) without Jon Lord is no Purple. One could say hard rock found its form and died with Deep Purple... Well, and some Hungarian bands that most folks here never heard: P. Box, P. Mobil, Dinamit, Hobo Blues Band; and Omega in the golden years (circa 1970-73). Jethtro Tull is the younger brothers of Purple & Sabbath in my ears a blind gate. Zeppelin is heavy blues like Hendrix. I dont buy the history writoing when Zeppelin is first and Purple after them. OK, maybe Zepp´lin helped pushed them in right direction... Together with other acts. Steppenwolf have been mentioned; and the Troggs. Free ought to be in too.
The Chocolate Watchband is represented in the Nuggets II-box ("Nuggets: Original Artyfacts from the First Psychedelic Era 1965-1968 [Box]" ) and is easy to get hold of, and the booklet in the boxis very informative (compiled with the cooperation of Jac Holzman and Lenny Kaye and other notable garage-rock aficionados as it is, words from [
www.notlame.com] ). Many of proto-hard rockers are... The Gonn with "Blackout of Gretely" are very hard. So is Electric Prunes with "I Had Too Much To Dream (Last Night)". Purple´s "Black Knight" was btw - they have revealed it themselves - ripped off from a Nuggets-tune: "We aint got nothin´ yet" with the Blues Magoos, written by Gilbert/Scala/Esposito. 124 songs, the booklet has 100 pages. See all titles at [
www.amazon.com]: a true trip in tock n´roll history.
The sound wall nowadays created by youngsters with lack of song material, roots or melodies as well as of harmony can be called anything... But hard rock. It´s just ~metal something.
Tracing hard rock back to blues roots seems reasonable. For what´s it worth.
The hardest of them all is the Stones, when in good shape.