What's an ancient story that's a good example for the plot structure of the monomyth, meaning most of the stations are there?
In my youth I read the popular classical Greek myths as well as a few German (Grimms fairytales, Nibelungenlied) and Norse sagas, and quite a few variations of the king Arthur stories. Either I forgot that some of them followed the monomyth plot structure, or none do, or I'm really bad at spotting plot structures. Supposedly the monomyth is everywhere, but the oldest example that comes to my mind is The Hobbit.
I've looked at wikipedia and these two TV Tropes pages, but the only examples mentioned where the bible (Jesus and Moses) and the life of Buddha. I'm interested in examples that are not (yawnsome) religious scripture.
So what is a good, pre-modern example of the monomyth in action? Which story follows the plot structure most closely?