diff --git a/source/impressum.md.erb b/source/impressum.md.erb
index ff209e4..c212f8e 100644
--- a/source/impressum.md.erb
+++ b/source/impressum.md.erb
@@ -15,3 +15,21 @@ E-Mail: <a href="mailto:<%= blog_author.email %>"><%= blog_author.email %></a>
 
 Diese Daten dürfen nicht zu Werbezwecken genutzt werden.<br>
 This data may not be used for advertising purposes.
+
+## License
+
+Unless noted otherwise on the respective pages the following licenses apply to
+content published on this website:
+
+* All written text of this website is licensed under [CC BY-SA 4.0](http://creativecommons.org/licenses/by-sa/4.0/).
+* Images published on this website are licensed under [CC BY-SA 4.0](http://creativecommons.org/licenses/by-sa/4.0/)
+  or their respective license. Please note the copyright and license statements
+  near the respective image.
+* Any published source code including the source of the website itself is
+  licensed under the [MIT license](https://opensource.org/licenses/MIT).
+
+This website uses various photos from [Unsplash](https://unsplash.com). The
+layout is based on [middleman-casper](https://github.com/danielbayerlein/middleman-casper)
+by Daniel Bayerlein licensed under MIT which in turn is based on the [Casper
+theme](https://github.com/TryGhost/Casper) for the [Ghost](https://ghost.org/)
+blogging platform.