What was the first Prog Album?

This thread has been very valuable to me for a variety of reasons, but one is Pssros' recommendation of EAST OF EDEN's ''Mercator projected''.    Now that I've heard some of that album, it clearly has something to offer/compete against ITCOTCK.   This is cool stuff.  BUT, did it come out before October 1969?   I can't find that anywhere?

 

Bruce Eder at All Music Guide says " It's also one of the most daring debut albums of its period, less tightly focused than, say, King Crimson's Court of the Crimson King but otherwise equally bold and maybe more challenging. The whole record is eerie — coming from a pop culture where most psychedelic rock tended toward the light and airy — the way the high-impact bass, drum, and guitar parts interact with the distinctly Oriental and Central/Eastern European classical influences. The title track is a surprise coming from any British psychedelic band of the period, opening with a pounding heavy metal beat pumped out on Steve York's bass and Dave Dufort's drums, while Dave Arbus' electric violin subs for what would normally be the rhythm guitar part and Geoff Nicholson's guitar twists a blues riff around before setting a Jimi Hendrix-like wave of tonal pyrotechnics ablaze for the finale. Though most of the rest isn't as hard rocking as that, it is still progressive rock with balls."

 

I may have found my answer, I just need a date. 

 

Also, learned that Fripp (Wakeman, Emerson) were influenced some by watching a band called 1,2,3 (later the Clouds) at the Marquee Club...but my ears tell me, its still more proto-Prog.

 

Still, clearly I needed to be a little more precise in my wording, but to deny that there is a certain ground zero factor of ITCOTKC is to fool one's self.  It may not be the first Prog album, if only because of various definitions of "Prog Rock",  but many "do" in fact consider it the "First" of something (i.e. modern Prog Rock).   There's a definate sound and approach to that album that is post-psych, and most certainly "Prog Rock" as most people define the term.  It was also hugely influential on future Prog rockers (including Yes and Genesis, who made their sound more complex after hearing ITCOTKC).

 

BUT, as I was celebrating, I now think East of Eden beat KC to the punch, with their sound.   (call it Prog rock or not).