Is there a single-word adjective describing something that has lasted forever? I'd be quite surprised if there wasn't. I can't ponder anything at the moment.
I'd imagine it's use to be something along "He bares the ancient prophecy". However ancient does not seem like a long enough time period. Eternal gives the impression that it will last forever. Whereas I'm looking for something that could last for a finite amount of time, however, has lasted since the start of time.
Edit: As pointed out, forever is very broad. And indeed I'm looking for broad answers. However, to be 100% clear. I'm looking for a word describing something that has existed since the start of time / the universe / the big bang. Something that defines an existence much longer than earth, not to mention humanity. I.e. the longest possible timespan between the past and now.