What is the {marriage} for {significant event} of {Franz Joseph I of Austria}
When is the {marriage} of {significant event} forf {Franz Joseph I of Austria}?
 select distinct ?obj where { wd:Q51056 wdt:P793 ?obj . ?obj wdt:P31 wd:Q8445 } 
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q51056> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P793> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q8445> } 
When is the {marriage} of {noteworthy occasion} forf {Franz Joseph I of Austria}?