Her mother died when she and Emma were still quite young, although she was older than her sister by a few years, so her mother wasn't just a distant memory as she was for Emma. Their father hired a governess, Miss Taylor, to care for them. Isabella was not as close with Miss Taylor as Emma was, although they were on good terms.
Isabella married John Knightley when Emma was about fourteen. She had five children Henry, John "Little John", Bella, "Little Emma", and George, often displaying concern for their health and comfort in a similar manner to her father.
Mrs. John Knightley is a pretty, elegant little woman, with quiet and gentle manners. Her disposition is amiable and affectionate, and is wrapped up in her family. She is a devoted wife and a doting mother, with very good ties with her father and sister. She inherited her father's constitution, and was delicate in her own health. She worried about the health of her children constantly.