What is the {empire} for {capital of} of {Istanbul}
What Domain utilized to have Istanbul as its capital ?
What Empire used to have Istanbul as its capital ?
SELECT DISTINCT ?f WHERE { ?f rdf:type ontology:empire . resource:Istanbul property:capital_of ?f }
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q406> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1376> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q48349> } 
 select distinct ?obj where { wd:Q406 wdt:P1376 ?obj . ?obj wdt:P31 wd:Q48349 } 