Professor Severus Snape was a half-blood wizard who was the son of the witch Eileen Snape (née Prince) and Muggle Tobias Snape. During his lifetime, Severus Snape was Potions master (1981–1996), Defence Against the Dark Arts professor (1996-1997), and Headmaster (1997-1998) of Hogwarts School of Witchcraft and Wizardry (which he attended as a student from 1971 until 1978). He was also member of the Order of the Phoenix, and played a very important role in both of the Wizarding Wars against Lord Voldemort.
Despite Severus Snape's wizarding heritage, he was raised in the Muggle dwelling of Spinner's End, which was in close proximity to the home of the Evans family. He met Lily and Petunia Evans when he was nine, and fell deeply in love with Lily, becoming a close friend of hers. In 1971 he began his first term at Hogwarts School of Witchcraft and Wizardry where he was sorted into Slytherin. Severus became the immediate enemy of James Potter and Sirius Black and was a frequent victim of their bullying. Snape developed a passion for the Dark Arts at a young age, and had followed the pure-blood supremacists in Slytherin House, despite his own marred pedigree and his love for Lily, a Muggle-born. This put his friendship with Lily under great strain. After leaving school he joined the Death Eaters along with a large group of his fellow Slytherins.