Background
Killigrew was the son of Sir Peter Killigrew (c1593-1668), Knight (4th son of John V Killigrew (c1557-1605), of Arwenack, Cornwall, Vice-Admiral of Cornwall and the third Governor of Pendennis Castle), Member of Parliament for Orkney, Shetland and Caithness in 1659 and for Helston in Cornwall from 1661 - July 1668, commonly known as Peter the Post, because of his great diligence in conveying messages to King Charles I during the Civil War. His mother was Mary Lucas, daughter of Thomas Lucas of Saint John"s Abbey, Colchester, and sister of Margaret Lucas, wife of William Cavendish, 1st Duke of Newcastle (1592-1676) and an attendant of Queen Henrietta Maria, wife of King Charles I, with whom she went into exile in France, having departed from Pendennis Castle near Arwenack, en route for the Scilly Isles.