what is the {start time} for {Margaret Mead} has {spouse} as {Gregory Bateson} ?
On what date did Margaret Mead wed Gregory Bateson?
When did Margaret Mead marry Gregory Bateson?
SELECT ?v WHERE { ?l property:start_time ?v . resource:Margaret_Mead property:spouse ?l . ?l property:spouse resource:Gregory_Bateson }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q180099> .
?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/Q314252> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q180099 p:P26 ?s . ?s ps:P26 wd:Q314252 . ?s pq:P580 ?value}