What is {spouse} of {Robert Schumann} that is {start time} is {1840-1-1} ?
Who is Robert Schumann's wife in 1840?
Who is the spouse of Robert Schumann in the year 1840?
SELECT ?n WHERE { ?u property:start_time ?k . FILTER ( CONTAINS ( YEAR ( ?k ) , '1840' ) ) . resource:Robert_Schumann property:spouse ?u . ?u property:spouse ?n }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q7351> .
?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> ?obj .
?statement <http://www.wikidata.org/entity/P580> <1840-1-1>
} 

SELECT ?obj WHERE { wd:Q7351 p:P26 ?s . ?s ps:P26 ?obj . ?s pq:P580 ?x filter(contains(YEAR(?x),'1840')) }