what is the {start time} for {London} has {twinned administrative body} as {Berlin} ?
About the administration of the respective cities, when did London and  Berlin got their first administrative body?
When did London and Berlin first have the same administrative body?
SELECT ?z WHERE { ?s property:start_time ?z . ?s property:twinned_administrative_body resource:Berlin . resource:London property:twinned_administrative_body ?s }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q84> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P190> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q64> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q84 p:P190 ?s . ?s ps:P190 wd:Q64 . ?s pq:P580 ?value}