Cross the styx

The following day Nigel apologized for what he described as an unhappy domestic interlude. “Marietta tells me that you are going to come over every day until . . . I cross the Styx.” I heard him chuckle. “Jolly nice of you, old boy.”

We know what’s sprouting, but Mantel’s trilogy lets us imagine that it might all have been different. Did Anne Boleyn’s neck have to meet the sword of an executioner brought from Calais to do her in? Did Thomas Cromwell have to cross the Styx himself four years later?