In “Harry Potter and the Half-Blood Prince,” numerous flashbacks delve into the Horcruxes and Voldemort’s history. Most are omitted from the films, except for the scenes where Dumbledore meets young Voldemort at the orphanage and the one involving Slughorn. Notably, one flashback, occurring before Voldemort’s birth, focuses on the Gaunt family. During this memory, the origins of a ring that belonged to the ancient pureblood Peverell family, which later becomes a Horcrux, are revealed.

Bob Ogden, a Ministry official who provided this memory to Dumbledore, visits the dilapidated Gaunt household to probe an assault on a non-magical Muggle. There, he encounters patriarch Marvolo and his children Merope and Morfin. Morfin had attacked a Muggle, and Marvolo interrupts Ogden’s investigation by brandishing a ring and exclaiming:

“See this? See this? Know what it is? Know where it came from? Centuries it’s been in our family, that’s how far back we go, and pure-blood all the way! Know how much I’ve been offered for this, with the Peverell coat of arms engraved on the stone?”

After the events of this memory, Merope elopes with a wealthy Muggle, Tom Riddle, who abandons her once she ceases dosing him with love potions. She gives birth to Voldemort and passes away, leaving Marvolo to die and Morfin to inherit the ring. Tom Marvolo Riddle, taking after his father and grandfather, later kills his uncle and takes the ring. As Dumbledore explains in “Half-Blood Prince,” he discovers the ring as a Horcrux and suffers greatly for it:

“The ring, Harry. Marvolo’s ring. And a terrible curse there was upon it too. Had it not been — forgive me the lack of seemly modesty — for my own prodigious skill, and for Professor Snape’s timely action when I returned to Hogwarts, desperately injured, I might not have lived to tell the tale. However, a withered hand does not seem an unreasonable exchange for a seventh of Voldemort’s soul. The ring is no longer a Horcrux.”

The ring, however, housed a Deathly Hallow — the Resurrection Stone — contributing to Dumbledore’s interest. Fortunately, by the time Harry learns it’s a Horcrux, it is already destroyed.