Question: When was Christiana Of Schleswig-Holstein-Sonderburg-Glücksburg's husband born?
Sentence (from "Friedrich Ferdinand, Duke of Schleswig-Holstein"): Friedrich Ferdinand of Schleswig- Holstein- Sonderburg- Glücksburg( 12 October 1855 – 21 January 1934) was the fourth Duke of Schleswig- Holstein- Sonderburg- Glücksburg and became Duke of Schleswig- Holstein in 1931.
Relevant evidence: No