what is the {start time} for {Philadelphia} has {capital of} as {United States of America} ?
What year did Philadelphia become a capital in the USA?
When did Philadelphia become capital of the USA?
SELECT ?c WHERE { resource:Philadelphia property:capital_of ?p . ?p property:capital_of resource:United_States_of_America . ?p property:start_time ?c }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q1345> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1376> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q30> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q1345 p:P1376 ?s . ?s ps:P1376 wd:Q30 . ?s pq:P580 ?value}