This concept had an early proponent in the Greek, late-fourth-century BCE writer, Euhemerus, giving his name to this approach to myth and legend: Euhemerism. Folklorists generally regard the idea that there was an actual basis for most oral tradition as barking up the wrong tree, because the original “real” event behind a story is usually elusive and searching for that core is a futile exercise. In addition, research into how stories began usually concludes that they emerge in a rather spontaneous way, typically without an actual incident to inspire them.

The idea of "the truth behind the legend" has been persistent if not always clearly stated. The Icelander, Snorri Sturluson in his Prose Edda of the thirteenth century, for example, wrote about the real people who he believed were behind the Norse gods, but we can wonder if Snorri wasn't directly drawing upon Euhemerus since he had apparently read some classics. My inclination is to see this part of Snorri's writing as responding to the former.

This is an adaptation of an an answer I provided about two weeks ago. These sorts of ideas are grounded entirely in speculation with no means to prove them; in addition, as I mentioned, folklore doesn't tend to work that way, so the answer is likely no.