Question: What is the date of death of Prince Boris Of Leiningen's father?
Sentence (from "Prince Karl of Leiningen"): Prince Karl Vladimir Ernst Heinrich of Leiningen (2 January 1928 – 28 September 1990) was the younger son of Karl, 6th Prince of Leiningen (1898–1946) and Grand Duchess Maria Kirillovna of Russia.
Relevant evidence: Yes