The Foremost Breakthroughs of Progressive Rock?

Good call on Procol Harum and Renaissance... I might add Fairport Conventions Debut album,  and 

Edited by Valdez - Yesterday at 12:27

Who yoo callin a Dinosaur???   

Czesław Niemen - Aerolit (1975) - the first Polish album to feature the Mellotron, which also happens to be prog.

Let's not ignore/discount the impact the Jazz-Rock Fusion movement and other periphery bands and genres had on progressive rock artists!

Edited by BrufordFreak - 21 hours 33 minutes ago at 18:45

I'm not sure about the dates in the OP as both the Procol Harum album and The Nice album were released in the same week and are generally cited tied 'first' as the earliest examples of albums having side long epics. 

Grumpyprogfan wrote: Not from the dinosaur prog days but in 1982, Allan Holdsworth releasing i.o.u. was a game changer.

For the jazz-rock genre, in my opinion, the game-changer could have been only Larry Coryell's Barefoot Boy, released in 1971, not an album released in the early 80s.

Sean Trane wrote: meAsoi wrote: Let's contemplate breakthroughs for the progressive rock genre; rather than just the mainstream success an album got for a single band in terms of sales, consider diving into the rich tapestry of musical innovation and contribution to counterculture in the late 60s and early 70s. Svettie, I'm not sure you know how to use the word "breakthrough" in the usual sense of the word in music. While your list makes sense (except for the one below), most of these albums are/were not massive commercial breakthrough (that's what was meant in the other thread). Whether Tresspass, NC, SEBTP or Lamb, Genesis' real breakthrough is really either ATTWT or Duke. What ou may mean with your current list is probably groundbreaking, and if the case, I will agree with your current list. meAsoi wrote: The Nice Ars Longa Vita Brevis (November 1968) . You seem to forget The Thoughts of Emerlist Davjack

Svettie? I thought we were talking about music, not Svetonio's fan club, to which you obviously belong since he is apparating for you everywhere! Well, as far as I know, in a musical context, a breakthrough refers to a significant advancement or development that changes the course of an artist's career as well as a new genre's evolution. Personally, I see 'breakthrough' as ​​something that resonates widely at a specific time. Prog was something new in 1968. Although it failed to chart, the aforementioned Ars Longa Vita Brevis received very positive reviews, and people were talking about the album. Symphonic prog made a breakthrough with that album. Melody Maker wrote, "A vast improvement on their first album, which shows them moving in a direction far removed from any other group, British or American." Additionally, the cover won that year's NME award for Best Pop Album Sleeve.

Valdez wrote: Good call on Procol Harum and Renaissance... I might add Fairport Conventions Debut album,  and  Steeleye spans "Parcel of Rogues" which had their hit 'Come ye all frae France.' (1973)

If Fairport Convention's 1968 debut gets on the list, we mustn't exclude Jethro Tull's This Was. Same year.

I guess I'm going to have to disagree about Trespass being their big prog breakthrough.I'd say Foxtrot at the earliest especially if we are talking the US.