what is the {start time} for {Franz Liszt} has {partner} as {Marie d'Agoult} ?
When did Franz Liszt commenced his engagement with his partner Marie d'Agoult?
When did Franz Liszt begin his relationship with his partner Marie d'Agoult?
SELECT ?c WHERE { ?u property:unmarried_partner resource:Marie_d'Agoult . ?u property:start_time ?c . resource:Franz_Liszt property:unmarried_partner ?u }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q41309> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P451> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q253453> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q41309 p:P451 ?s . ?s ps:P451 wd:Q253453 . ?s pq:P580 ?value}