Question: What is the date of death of Friedrich, Duke Of Schleswig-Holstein-Sonderburg-Glücksburg's mother?
Sentence (from "Friedrich, Duke of Schleswig-Holstein-Sonderburg-Glücksburg"): Friedrich inherited the title of Duke of Schleswig-Holstein-Sonderburg-Glücksburg upon his childless brother Karl's death on 14 October 1878.
Relevant evidence: No