what is the {point in time} for {Jan Brueghel the Elder} has {work location} as {Prague} ?
Tell me when Prague was the city in which Jan Brueghel the Elder worked.
When did Jan Brueghel the Elder work in Prague?
SELECT ?z WHERE { ?k property:point_in_time ?z . ?k property:work_location resource:Prague . resource:Jan_Brueghel_the_Elder property:work_location ?k }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q209050> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P937> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q1085> .
?statement <http://www.wikidata.org/entity/P585> ?value. 
} 

SELECT ?value WHERE { wd:Q209050 p:P937 ?s . ?s ps:P937 wd:Q1085 . ?s pq:P585 ?value}