what is the {start time} for {Ivan the Terrible} has {spouse} as {Anna Koltovskaya} ?
When was the wedding of Anna Koltovskaya and Ivan the Terrible?
When did Ivan the Terrible marry Anna Koltovskaya?
SELECT ?a WHERE { ?x property:spouse resource:Anna_Koltovskaya . resource:Ivan_IV_Vasilyevich property:spouse ?x . ?x property:start_time ?a }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q7996> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P26> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q151587> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q7996 p:P26 ?s . ?s ps:P26 wd:Q151587 . ?s pq:P580 ?value}