The liturgical poem beginning "Adon olam" is often sung (including as part of prayer services) to the same tune as "The Poet and the Prophet". Was that tune originally to (i.e. written for) Adon Olam? If so, who wrote it and when? If not, who put it to Adon Olam and when?
When The Village Stompers first released it in 1963, we believed that it was indeed an instrumentalization of (an already existing tune for) Adon Olam. I do not know if they ever "officially" announced it as such, but it seemed obvious (to us) that it was the same. I do know that we used it at summer camp. I think that the summer camp was the summer before, because I went to Eretz Yisrael the next summer (1964) I do know that after it was released, we all assumed that it had been based on Adon Olam.
Of course since it was so long ago, I could be mistaken about having heard it that summer and conflated it with having heard it during the trip to Israel (the following summer). Even if it was based on Adon Olam, the author could have written an original tune for it. Since it was over 50 years ago, I can no longer be sure.
Note that I have found comments of people who recognized it as Adon Olam, but no references going that far back.
I did find Poet and The Prophet lists the authors as Joe Sherman(C) and George David Weiss(A)
Copyright date is shown as 20 December 1963.
Of course, given our "musical knowledge" at that time, it could have been the reverse and we still would have believed it.
See the answer by @ShamanSTK who seems to be able to connect it to a melody that was used in (at least) the 1950's that may have been the base of the song that Sherman wrote for the Village Stompers.
This tune for Adon Olam appears as early as 1897 when published by Eliezer Gerovitch (Eliezer ben Yitzchok Gerowitsch 1844-1913) in his שירי תפילה. It is not certain whether he composed it or whether he was transcribing a tune of earlier origin that he knew.
Joe Sherman and George David Weiss who were Jewish and born in the 1920s, likely heard this very popular tune in their childhood.
This is one of many places that ascribe the tune to Gerovitch.
For more information on Eliezer Gerovitch see the following:
Library listings for שירי תפילה appear here
Salamone de Rossi, a renaissance composer, wrote an Adon Olam. The base line sounds like the modern tune to my ears. YouTube link.