Question: Which royal person married the successor of Darius I?
SPARQL:
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/property/predecessor> <http://dbpedia.org/resource/Darius_I> . ?uri <http://dbpedia.org/property/spouse> ?x  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Royalty>}