Who is believed to be Constantina's father in the novel, The Weight of Ink?

Limited information is provided on the unnamed Englishman and father of Constantina, whose potential identity establishes an unexpected twist at the end of the novel. Lizabeta described the man as having charmed all of England with his words; they were both married to others, and he had told Lizabeta that she possessed “a beauty to tempt away a man’s better angel, corrupting his saint to be the very devil” (553). These words are repeated by both Ester and Constantina and closely resemble a phrase used by Shakespeare to describe his Dark Lady. The novel concludes with the possibility that Ester’s Portugese-Jewish grandmother had been Shakespeare’s famous lover outside of marriage and that Ester herself descended from him.