The Hour of Gaunt

Dumbledore begins showing Harry memories of Voldemort's past using the Pensieve. They first view a memory of Bob Ogden, a Ministry official, visiting the Gaunt family. The Gaunts are the last descendants of Salazar Slytherin, living in poverty and squalor. Marvolo Gaunt, his son Morfin, and his daughter Merope are introduced. Morfin attacks a Muggle, Tom Riddle Sr., and is later arrested. The memory reveals that Merope is in love with the Muggle, and that she is Voldemort's mother. Dumbledore explains that Merope used a love potion to ensnare Tom Riddle Sr., but he abandoned her when she stopped using it. She died shortly after giving birth to Tom Riddle Jr. in an orphanage.