diff --git a/ghc-shelly.spec b/ghc-shelly.spec
index 183c0d2..d0270b3 100644
--- a/ghc-shelly.spec
+++ b/ghc-shelly.spec
@@ -37,6 +37,8 @@ POSIX shells. Shelly:
 * maintains its own environment, making it thread-safe.
 * is modern, using Text and system-filepath/system-fileio
 
+Shelly is originally forked from the Shellish library.
+
 An overview is available in the README:
 <https://github.com/yesodweb/Shelly.hs/blob/master/README.md>.