what is the {start time} for {Venice} has {country} as {Republic of Venice} ?
What was the date when Venice had its name changed to the Republic of Venice?
When did Venice become the Republic of Venice?
SELECT ?v WHERE { ?a property:start_time ?v . ?a property:country resource:Republic_of_Venice . resource:Venice property:country ?a }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q641> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P17> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q4948> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q641 p:P17 ?s . ?s ps:P17 wd:Q4948 . ?s pq:P580 ?value}