diff --git a/vocabulary.ttl b/vocabulary.ttl
index afc77a6..f1749f4 100644
--- a/vocabulary.ttl
+++ b/vocabulary.ttl
@@ -39,7 +39,7 @@ ldes:EventSource rdfs:subClassOf tree:ViewDescription ;
                  rdfs:label "Event Source"@en ;
                  rdfs:comment "A data service that provides the source other views should synchronize with"@en .
 
-ldes:RetentionPolicy a rdf:Class ;
+ldes:RetentionPolicy a rdfs:Class ;
                      rdfs:label "Retention Policy"@en ;
                      rdfs:comment "The abstract concept of a retention policy."@en .
 
@@ -98,4 +98,4 @@ ldes:versionMaterializationUntil a rdf:Property ;
                    rdfs:label "Version Materialization Until"@en;
                    rdfs:comment "Timestamp until versions were processed"@en ;
                    rdfs:range xsd:dateTime ;
-                   rdfs:domain tree:Collection .
\ No newline at end of file
+                   rdfs:domain tree:Collection .