Severus Snape was born on January 9, 1960, to Tobias Snape, a Muggle, and Eileen Prince, a witch. His childhood was difficult, as his father was harsh and indifferent to the family, often acting cruelly toward both Severus and Eileen. This drove the boy to seek solace in magic, which he began exploring from a very young age. Severus grew up in a dilapidated house in a Muggle neighborhood known as Spinner's End.

In his childhood, he met Lily Evans, a future Gryffindor student who lived nearby. Lily became his first and possibly only true friend. Severus was captivated by her magical abilities and kindness, and she helped him avoid complete alienation from the world.

Severus enrolled at Hogwarts in 1971 and was sorted into Slytherin. From the very beginning, he demonstrated exceptional talent in Potions, Defense Against the Dark Arts, and magical spells. His abilities were so remarkable that even professors like Horace Slughorn took notice of him.

Snape quickly became fascinated with the Dark Arts, reading extensively about them and experimenting. During this time, he began inventing his own spells, such as Sectumsempra, one of his most dangerous creations. He signed his notebook as the Half-Blood Prince, combining the legacies of his witch mother and Muggle father.

Severus's relationship with James Potter, Sirius Black, Remus Lupin, and Peter Pettigrew (the Marauders) was tense from the start. James and Sirius often bullied him for his appearance, behavior, and background. The most humiliating incident occurred after a Defense Against the Dark Arts lesson when James used the Levicorpus spell to suspend Severus upside down in the air in front of a crowd of students. This event left a deep scar in Snape's memory, intensifying his hatred for James.