Yes they did.
They played a piece from some classical 1600 concerto this morning on a local radio station Sounded identical to the intro to Stairway to Heaven.
I listened to both intros to each sone, and they don’t even remotely sound alike.
Yes they did.
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Spirit was not the first musical act to play a descending chromatic line from A down to F with the harmony looking like a pretty standard minor key progression.
The key of Am is established in the first measure with the tonic and the (altered) dominant being played.
At least that’s what my ear tells me.
Somebody owes George Harrison a big apology.