what is the {start time} for {George Grenville} has {position held} as {Prime Minister of the United Kingdom} ?
When did George Grenville gotten to be Prime Serve of the Joined together Kingdom?
When did George Grenville become Prime Minister of the United Kingdom?
SELECT ?f WHERE { ?e property:position_held resource:Prime_Minister_of_the_United_Kingdom . resource:George_Grenville property:position_held ?e . ?e property:start_time ?f }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q244616> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P39> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q14211> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q244616 p:P39 ?s . ?s ps:P39 wd:Q14211 . ?s pq:P580 ?value}