Isabel was the second daughter of her parents (Williamson, David. Debrett's kings and queens of Europe. Topsfield, Mass. : Salem House Publishers, pg. 229). (The concise dictionary of national biography. Part 1 : from the beginning till 1900. London : Oxford University Press, 1969, pg. 159). aka Isabella (Browning, Charles. Americans of royal descent, 7th ed. Baltimore : Genealogical Pub. Co., 1986, pg. 189).