Godelot is known to have perished in his own cellar, where he was locked by his mad son, Hereward.
-- Albus Dumbledore, writing in his annotations for Tales of Beedle the Bard (TBB/TTB)
Godelot owned the Elder Wand, which he spoke of almost as a friend or mentor in the Dark Arts. His son, Hereward, coveted the wand and that jealousy eventually led him madness. He stole the wand and locked his father in the cellar, where Godelot died.
The date for Godelot's death is based on Dumbledore's note that the infamous Dark Wizard lived "a full century" after Emeric The Evil, who lived in the early Middle Ages. That era is generally defined as being from the 500s through the 900s. For the sake of our timeline, we assume the Emeric lived around 700 and Godelot around 800 AD.