Tom Marvolo Riddle & the Riddle Family
The Riddle family was a singularly unpleasant, upper class family who fifty years ago lived in the village of Little Hangleton in a large manor house ('Riddle House') on a hill, overlooking a graveyard and a church.
Tom Marvolo Riddle, Jr./Lord Voldemort: Born of a witch mother (Merope Gaunt) and a Muggle father (Tom Riddle, Sr.) on December 31, 1926 [year is approximate]. His mother had fallen in love with his father, who was a Muggle, and tricked him into marrying her with a love potion. While she was pregnant with Tom Jr. she allowed the love potion to wear off and he abandoned her and moved back into the Riddle house with his parents. Merope died giving birth to her son so Tom Jr. was raised in a Muggle orphanage.
Tom grew up to be a very powerful wizard. He excelled at Hogwarts, winning awards for service to the school and magical merit. He was even head boy in his seventh year, but he was already dabbling in the Dark Arts while still at school. Some of his closest friends in Slytherin were already calling him Voldemort, a name Riddle had chosen by rearranging the his given name into "I am Lord Voldemort." (PS17)
After leaving Hogwarts, Riddle began working at Borgin and Burke's in Knockturn Alley. His job was to ferret out items of value and obtain them at the lowest price possible. He disappeared one day (after murdering Hepzibah Smith), and when he returned he was known only as 'Lord Voldemort.' Few people except perhaps for Dumbledore and his early followers remembered the Dark Lord's origins. SEE 'Lord Voldemort' for much more information.
Tom Riddle, Sr., father to Tom Riddle Jr. [Muggle] An "anti-magic, rich, snobbish & rude" person who abandoned his pregnant wife and unborn son when she revealed that she was a witch (CS17 & GF33). Tom Riddle, Jr. got his revenge when he killed his father along with his paternal grandparents c.1945, and used his father's death to create his first Horcrux, the Peverell Ring (BLC). Later, some of Tom Riddle Sr.'s bone was removed from his grave ("bone of the father, unknowingly given") to add to the potion that allowed Voldemort to regain his full powers (GF32, GF33).
Grandparents: Mr. and Mrs. Riddle [Muggles] -- Paternal grandparents of Tom Riddle Jr. Killed by him c.1945.
Merope (Gaunt) Riddle: married Tom Riddle Sr. through the use of a love potion; however, he left her when it wore off about a year later. She died in London at a Muggle orphanage after giving birth to Tom. Merope was a descendent of Salazar Slytherin; her father was named Marvolo Gaunt. (More...)
RIDDLE in the MOVIES
"Harry Potter and the Sorceror's Stone:" Voldemort (in the flashback) is played by Richard Bremmer; in the Mirror of Erised scene he is voiced by Ian Hart.