Everybody I think is familiar with one or more Legends that came from Greek mythology. Hercules or to give him his correct name, Heracles, and his labours, Perseus and the slaying of Medusa, Jason and the Argonauts, Theseus and the Minotaurus.

There is the theory that the myths were mostly based on events that happened, events that seemed so extraordinary at the time, that only
divine intervention could explain them.
There probably was somebody called Heracles, born in Tyrins, a man of extraordinary strenght and bravery.
There were plagues of birds pestering the inhabitants around the Lake of Stymphalia.
There might have been a man-eating (or sheep-eating) beast, in the plain of Nemea. Whether Heracles took care of them or not, his name, him being in the neighborhood so to speak, was associated with them. From then on the Legend grew.

As for Homer's epic heroes, scholars and archeologists insisted that they were all figments of his very fertile imagination. It took SCHLIEMAN, a merchant from Germany, admirer of the poet, to prove them wrong. He found Troy and Myceneai, he even found Agamemnon's grave and treasure. Today still, some scholars insist, that Achileus, Odysseus and the rest of them, were fictitious. Until another Schlieman appears and proves them wrong yet again.

The various gods have their own legends too.
Zeus with his roving eye created a lot of problems for his long suffering wife Hera. Especially since she was the godess protecting marriage, home and family among other things. Each of his escapades served to give an explanation in theogony.The birth of Apollo and Artemis (Sun and Moon), the abduction of Evropi (creation of Europe) etc.
This is common in all religions. To understand phenomena, physical, or metaphysical there must be an explanation given which would satisfy mere mortals.
It was much later, in the 5th century B.C., during the Golden Age, that the divine legends explaining natural phenomena were gradually discarded, and new theories were formulated based on logic. These theories are the basis of our science today.


Detail, Hermes of Praxiteles.
Olympia Museum
Aesop's Fables is another kind of mythos. Nobody really knows who Aesop was or where or when did he live. They say he was a Phrygian slave.They also say that he was not really the author of all the Fables. Whatever the truth, his Mythoi were typical Greek in their inspiration and formulating. He cauterizes human and especially political frailties in the form of allegories. Children still wallow in them, while grown-ups feel a bit unconfortable reading them.
His style was later adopted by Aristophanes in his satirical plays. Jean de la Fontaine borrowed a lot from Aesop for his own Fables.
Here's one that I find very instructive:
At one time, the god Hermes, curious as to what mortals thought of him, took up his human disguise and went into a market place.
He strolled into a sculptor's studio, whose specialty was statues of the gods. Looking around, he asked the price of a couple of statues of Zeus and Hera.
After the man gave him the prices, he casually pointed to a statue of himself and remarked:" Surely, this one must cost more than the others, since Hermes is not only the messanger of the gods, but your patron God, as he is also the God of Profit"
"I'll tell you what," answered the man. "You buy the other two, and I'll throw Hermes in for free......"