Question: What were the names of Queen Victoria's parents who died on 1820-01-23?
Answer(s):
answer: Prince Edward, Duke of Kent and Strathearn

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.0cw10)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.0cw10 ns:people.person.parents ?x .
?x ns:people.deceased_person.date_of_death "1820-01-23"^^xsd:dateTime . 
}