what is the {end time} for {Al-Mansur} has {position held} as {Abbasid caliph} ?
When did Al-Mansur end his rule as Abbasid Caliph?
SELECT ?value WHERE { wd:Q31066 p:P39 ?s . ?s ps:P39 wd:Q28541943 . ?s pq:P582 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q31066> .
?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/Q28541943> .
?statement <http://www.wikidata.org/entity/P582> ?value. 
} 

On What data did Al- Mansur end his rule as Abbasid Caliph?