what is the {instance of} for {Oleg of Novgorod} has {date of birth} as {900-1-1} ?
What position did Oleg of Novgorod, born in the year 900 AD hold?
SELECT ?value WHERE { wd:Q6131983 p:P569 ?s . ?s ps:P569 ?x filter(contains(?x,'900-1-1')) . ?s pq:P31 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q6131983> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P569> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <900-1-1> .
?statement <http://www.wikidata.org/entity/P31> ?value. 
} 

In 900 AD Oleg of Novforod held what position?