You may take your pick. I was taught the mythology arose in Greece. Some sources state Egypt ~ which is disputed due to the corruption of original sources. The Egyptian story is quite different to the one we commonly know.I'm not sure who first thought up the phoenix, Ribh might know, but many say it's an ancient Egyptian figure. Anyway, it's a readily understood and inspirational fiction analogous to much of how people experience life. Peaks and troughs, peaks and troughs, the emotional rhythm of humanity.