Harry Potter’s mother, Lily, originally had the surname Evans in J.K. Rowling’s books.
Lily Evans was born to Muggle parents and had an older sister, Petunia. She was a witch and attended Hogwarts, where she became friends with Severus Snape and later married James Potter. After her marriage, she was known as Lily Potter.
Lily’s family background is important because it establishes Harry as a half-blood wizard: his mother was magical, while his father was also a wizard. Her sister Petunia remained outside the magical community and resented the attention Lily received for being different.
Lily’s death while protecting Harry is central to the series. Her deliberate sacrifice creates a magical protection that prevents Lord Voldemort’s killing curse from destroying Harry. The protection is one reason the infant Harry survives the attack that kills his parents and leaves him with his lightning-shaped scar.