Did Harry Potter and Tom Riddle share any ancestors?
Tom Riddle and Harry Potter share ancestry in two of the Peverell brothers, Cadmus and Ignotus.
Cadmus’s ring, the Resurrection Stone, was a family heirloom, according to Marvolo Gaunt, Voldemort’s grandfather. Evidently someone from the Peverell family must have married an heir of Salazar Slytherin, this leading to the Gaunts.
Ignotus’s cloak, the Invisibility Cloak, was a family heirloom that was passed down through the Potters, also probably through a daughter of the Peverells’.