Question: What is the date of death of Princess Luise Of Schleswig-Holstein-Sonderburg-Beck's husband?
Sentence (from "Frederick Ferdinand, Duke of Anhalt-Köthen"): Frederick Ferdinand of Anhalt-Köthen (25 June 1769, Pless – 23 August 1830, Köthen) was a German prince, Ascanian ruler of the principality of Anhalt-Pless and, from 1818, of the duchy of Anhalt-Köthen.
Relevant evidence: Yes