what is the {start time} for {Republic of Florence} has {instance of} as {historical country} ?
On what date did the Republic of Florence because its own nation?
When did the Republic of Florence become a country?
SELECT ?n WHERE { ?u property:start_time ?n . ?u rdf:type ontology:historical_country . resource:Republic_of_Florence rdf:type ?u }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q148540> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P31> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q3024240> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q148540 p:P31 ?s . ?s ps:P31 wd:Q3024240 . ?s pq:P580 ?value}