First used in Egyptian art as far back as 3.300 B.C., the Griffin is one of the most spread mythological characters in the world. It is a legendary creature with the body of a lion and the head and wings of an eagle and was believed that it had a protective role against evil and witchcraft and it was a simbol for courage and boldness (in heraldry).
In antiquity it was a symbol of divine power and a guardian of the divine.

Griffins not only mated for life, but also, if either partner died, then the other would continue throughout the rest of its life alone, never to search for a new mate. For this reason we think it was a very lonely “bird” and could be the reason it disappeared. 😀

Griffins, like many other fictional creatures, frequently appear within works under the fantasy genre. Examples of fantasy-oriented franchises that includes griffins include Warcraft, Dungeons and Dragons, Ragnarok Online, Harry Potter, and The Spiderwick Chronicles.

One theory, postulated primarily by Adrienne Mayor, is that the griffin’s origins are based in ancient paleontological observations brought by long-distance traders to Europe along the Silk Road from the Gobi Desert in Mongolia, where fossils of Protoceratops and their nests and eggs are naturally exposed. Such fossils, seen by ancient observers, may have been interpreted as evidence of a half-bird-half-beast.

More details on Wikipedia.