diff --git a/README.md b/README.md
index 4fb7505..69526ef 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 Date::Performance
 =================
 
-This package adds some semblance of performance to Ruby's core Date class 
+This package adds some semblance of performance to Ruby 1.8's core Date class 
 using a combination of different techniques:
 
 1. Implements various core *Date* methods in C. This is nowhere near a