 When Boyle arrived back in England in mid-1644 at the age of 17 he was quickly reunited with his sister Katherine who seems immediately to have re-adopted the semi-maternal role she had no doubt often played after the death of their mother. She was concerned in a variety of other ways to look after his welfare, both spiritual and worldly. She was, for example, the immediate cause of his getting to know the members of the Hartlib  circle.[12]