diff --git a/referer_parser/__init__.py b/referer_parser/__init__.py
index c49834a..110eccc 100644
--- a/referer_parser/__init__.py
+++ b/referer_parser/__init__.py
@@ -34,7 +34,6 @@ def load_referers(json_file):
 
 class Referer(object):
     def __init__(self, ref_url, curr_url=None, referers=REFERERS):
-        self.known = False
         self.referer = None
         self.medium = 'unknown'
         self.search_parameter = None
@@ -62,6 +61,7 @@ def __init__(self, ref_url, curr_url=None, referers=REFERERS):
             referer = self._lookup_referer(ref_host, ref_uri.path, False)
             if not referer:
                 self.medium = 'unknown'
+                self.known = False
                 return
 
         self.referer = referer['name']