Your Marie Louise Rantzow (or Rantzau) Jacobs was one of eleven children of Dr. William Stephen Jacobs and Juliette Marie Elizabeth v. Rantzow (B. July 9,1835). Marie was the sister of my great grandfather, Ferdinand Anton Rantzow J. Ferdinand was born in Christiansted, St. Croix, D.W.I (now U.S. Virgin Islands) January 6, 1828.
Dr. W.S. Jacobs was born in Brussels, Belgium March 4, 1772 (?) and died Dec. 30, 1843 in Christiansted. His wife, Juliette, was born in Copenhagen, Denmark on Mar. 19, 1801. She held the title of countess. She may have also been listed as the Baroness v. Brockenburg. She died March 19, 1870 in Christiansted.
Juliette was the daughter of Count Julius Frederick Ludwig v. Rantzau and Elizabeth De Wint. The De Wint family owned many plantations on the Island of St. Croix. Elizabeth was the daughter of the King's General Commissioner for War, Guert Sprewert De Wint and Judith Heyliger.
The father of Count Julius was Count Christopher Anton Ferdinand von Rantzow who was at one time the high bailiff of Ceylon during the Dutch occupation of that island. In 1759, Christopher married his second wife, Louise Henriette, the Baroness von Brockenburg.
Your Marie Louise (my gr. aunt), married Bentzon Danielson in 1854. This was her second marriage. She died in Charlotte Amalie, St. Thomas, D.W.I. in 1884.
Through the Rantzow line, your Marie Louise is related to most of the crown heads of Europe. I have much information on these connections.
I hope you find this helpful to your search.