diff --git a/reference/math/functions/log.xml b/reference/math/functions/log.xml
index 942d0c308f..54c835174c 100644
--- a/reference/math/functions/log.xml
+++ b/reference/math/functions/log.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.3 $ -->
+<!-- $Revision: 1.4 $ -->
 <!-- splitted from ./en/functions/math.xml, last change in rev 1.2 -->
   <refentry id="function.log">
    <refnamediv>
@@ -11,10 +11,20 @@
      <methodsynopsis>
       <type>float</type><methodname>log</methodname>
       <methodparam><type>float</type><parameter>arg</parameter></methodparam>
+      <methodparam choice="opt"><type>float</type><parameter>base</parameter></methodparam>
      </methodsynopsis>
     <para>
-     Returns the natural logarithm of <parameter>arg</parameter>.
+     If the optional <parameter>base</parameter> parameter is specified, 
+     <function>log</function> returns log<subscript>base</subscript>
+     <parameter>arg</parameter>, otherwise <function>log</function> 
+     returns the natural logarithm of <parameter>arg</parameter>.
     </para>
+    <note>
+     <para>
+      The <parameter>base</parameter> parameter became available
+      with PHP verion 4.3.0
+     </para>
+    </note>
    </refsect1>
   </refentry>