What is {spouse} of {Lord Byron} that is {start time} is {1815-1-1} ?
Lord Byron's wife in January 1st 1985?
Who is the spouse of Lord Byron as of January 1st 1815?
SELECT ?d WHERE { FILTER ( CONTAINS ( YEAR ( ?c ) , '1815' ) ) . ?u property:spouse ?d . ?u property:start_time ?c . resource:Lord_Byron property:spouse ?u }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q5679> .
?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> <1815-1-1>
} 

SELECT ?obj WHERE { wd:Q5679 p:P26 ?s . ?s ps:P26 ?obj . ?s pq:P580 ?x filter(contains(YEAR(?x),'1815')) }