diff --git a/doc/23-migrating-from-icinga-1x.md b/doc/23-migrating-from-icinga-1x.md
index 14a30cf2e..22954b557 100644
--- a/doc/23-migrating-from-icinga-1x.md
+++ b/doc/23-migrating-from-icinga-1x.md
@@ -1,4 +1,8 @@
-# Migration from Icinga 1.x <a id="migration"></a>
+# Migration from Icinga 1.x or Nagios <a id="migration"></a>
+
+!!! note
+
+    Icinga 1.x was originally a fork of Nagios. The information provided here also applies to Nagios.
 
 ## Configuration Migration <a id="configuration-migration"></a>