diff --git a/History.rdoc b/History.rdoc
index 18764b0f95..b7e20ca0d2 100644
--- a/History.rdoc
+++ b/History.rdoc
@@ -10,7 +10,6 @@
 
 * Minor enhancements
   * Improve class name expansion/resolution in ri.  PR #400 by NARUSE, Yui
-  * Improve performance of document generation. PR #397 by Yusuke Endoh.
 
 === 4.2.2 / 2016-02-09