Hello Jim,
Robert Callister ack a legacy of one guinea from his sister Margaret garret. I think it most likely they shared the same mother. Margaret also mentions her sister in law Elizabeth Christian als Corlet widow, of the dec'd John Christian of the Curragh in the parish of lezayre. The will of John Christian 1792 is on the iom fhs website.Also the will of his wife Elizabeth 5 Dec 1793. John Christian married Elizabeth Corlet 11 Feb 1737 at Lezayre. They had 8 children. Margaret does not mention any children of her own or of her Dec'd husband. I would think Marg't and her brother John Christian were born very early 1700's. I tried the igi for Margaret Christian bir/chr but there are so many lds member submitted that are so obviously guesses.

Pauline