Kingsley, Florence Morse: Prisoners Of The Sea. v1. 11 Dec 2015
 

Florence Morse Kingsley (July 14, 1859 – November 7, 1937) was an American authoress of popular and religious fiction.

Excerpt
“The Man with the Iron Mask” is the strangest figure in all history. The facts presented in the preceding narrative determine the identity of this sphinx-like apparition, and that without a shadow of doubt. The document containing these facts, as set down by the hand of Henri Baillot, Comte de Lantenac, was preserved for many years with other family papers in the very treasure-cask which figures in the story. When it lately fell into the hands of the author there seemed no longer any reason why the story should not be told.