Their graves are everywhere. People say there is where this and that giant is buried. Cities and towns are named after them. The stories always reveal, to someone familiar with the Nephilim subject in the Bible and the Book of Enoch, a remarkable relationship, and similarity.
Did medieval people know about the Genesis 6 giants and the more detailed description in the Book of Enoch? No, there is no record of them knowing more than what the church had taught, which was only fragmentary. And still, the stories about giants and trolls (a sub species of
the giants) seem to reveal a great knowledge in the relations of the nephilim (and their dealings with mankind). Which then only would be explained if they really were here, and left that knowledge behind, just as the giants of old did, in the ancient Middle East.