On gospel and Azerbaijan

A few weeks ago, I conspired once more with choir director Stephanie Beekmans to put together the end-of-year presentation with Trias' "Van Bach tot Beatles" choir.
As usual, it was great fun. There was gospel singing, lots of Mozart (including a transposed version of Liszt's transcription of the Ave Verum) and even some Leonard Cohen, in the form of Hallelujah.
For me, the Hallelujah is always a favorite. A long long time ago, one of my high school friends had some skills with a guitar, and this was one of the songs he delighted to make us all sing along with. To my glee, I still know the lyrics off by heart.
There was also a Beatles medley presented by the Rijswijks Gemeentekoor, who were accompanied not only by their choirmaster on a double bass but also a student on an electric guitar, and I must say - it was rather impressive!
But the most interesting part of the evening for me was right before the performance. I'd thought to provide some ambience while the audience came in, and played Satie's Gnossienes and Gymnopedies.
Whilst I was fiddling with the first Gnossiene, a lady from the Gemeentekoor walked over to me and asked what I was playing. I told her it was French music, inspired by Greek themes. She said, no, this is Azerbaijan music - and proceeded to sing along with all of the melody, excepting the six-tone-scale bit that makes up the third part of the melody.
Up to and including all the grace notes, might I add.
She then went on to point out that this was a well-known lament from her culture.
I of course pressed on and asked her if she knew the melody for any of the other Gnossienes. Unfortunately, her knowledge only extended to the first.
So, here we have something interesting to research. Does the Azerbaijan theme predate Satie's interpretation, and if so, how did a French composer in the 1890's come to hear it? To my knowledge, he never travelled to that part of the world - although I must admit my knowledge is rather limited on the subject.
It would be even more unlikely to say that in the span of less than a hundred years a rather fancy impressionistic tune (which is, in addition, fairly hard to hum) would travel all the way to Azerbaijan to become so ingrained in the culture there that it's now described as a well-known folk tune.
This is a mystery that must be solved. Hopefully sooner rather than later, but who knows when I'll have the time to properly look into it...
Intrigue!