When Dumbledore went to Hogwarts he became good friends with the head girl of Ravenclaw. She was really good at magic and top of her class. She could do any speel she wanted and even made a few in her time.

Instead of becoming a witch, she went to become a nanny in the muggle world. Before she left her and Dumbledore swaped their house scarves so they could remember each other.

Her name? Mary Poppins of courses.