diff --git a/include/cowl_manager.h b/include/cowl_manager.h
index 723b35c..de56681 100644
--- a/include/cowl_manager.h
+++ b/include/cowl_manager.h
@@ -172,6 +172,7 @@ CowlOntology *cowl_manager_new_ontology(CowlManager *manager);
  * @note You can pass NULL as the IRI and version, in which case the function returns
  *       a new anonymous ontology.
  */
+COWL_DEPRECATED(Use @func{cowl_manager_retrieve_ontology()} or @func{cowl_manager_new_ontology()}.)
 COWL_API
 COWL_RETAINED
 CowlOntology *cowl_manager_get_ontology(CowlManager *manager, CowlIRI *iri, CowlIRI *version);
@@ -183,6 +184,9 @@ CowlOntology *cowl_manager_get_ontology(CowlManager *manager, CowlIRI *iri, Cowl
  * @param iri The ontology IRI.
  * @param version The ontology version.
  * @return Ontology with the specified IRI and version, or NULL if it does not exist.
+ *
+ * @note Passing NULL as the version retrieves the ontology with the specified IRI
+ *       and either NULL version (if it exists) or any other version.
  */
 COWL_API
 CowlOntology *cowl_manager_retrieve_ontology(CowlManager *manager, CowlIRI *iri, CowlIRI *version);
diff --git a/src/cowl_manager.c b/src/cowl_manager.c
index 6551bfb..287396e 100644
--- a/src/cowl_manager.c
+++ b/src/cowl_manager.c
@@ -252,13 +252,13 @@ CowlOntology *cowl_manager_get_ontology(CowlManager *manager, CowlIRI *iri, Cowl
 }
 
 CowlOntology *cowl_manager_retrieve_ontology(CowlManager *manager, CowlIRI *iri, CowlIRI *version) {
+    CowlOntology *match = NULL;
     uvec_foreach (CowlObjectPtr, &manager->ontos, onto) {
-        if (cowl_ontology_get_iri(*onto.item) == iri &&
-            cowl_ontology_get_version(*onto.item) == version) {
-            return *onto.item;
-        }
+        if (cowl_ontology_get_iri(*onto.item) != iri) continue;
+        match = *onto.item;
+        if (cowl_ontology_get_version(*onto.item) == version) break;
     }
-    return NULL;
+    return match;
 }
 
 cowl_ret cowl_manager_add_ontology(CowlManager *manager, CowlOntology *onto) {