diff --git a/public/404.html b/public/404.html
index 0e184561..5f17be38 100644
--- a/public/404.html
+++ b/public/404.html
@@ -1,8 +1,10 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
-   "http://www.w3.org/TR/html4/loose.dtd">
-<html>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd" >
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
+<head>
+<title>404</title>
+</head>
 <body>
   <h1>File not found</h1>
-  <p>Change this error message for pages not found in public/404.html</p>
+  <p>You were, perhaps, looking for <strong>cheese</strong>?</p>
 </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/public/500.html b/public/500.html
index a1001a00..67a87ceb 100644
--- a/public/500.html
+++ b/public/500.html
@@ -1,8 +1,10 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
-   "http://www.w3.org/TR/html4/loose.dtd">
-<html>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd" >
+<html  xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
+<head>
+<title>500</title>
+</head>
 <body>
   <h1>Application error (Apache)</h1>
-  <p>Change this error message for exceptions thrown outside of an action (like in Dispatcher setups or broken Ruby code) in public/500.html</p>
+  <p>Something <em>very bad</em> just happened. I just <em>know it</em>. Do you smell smoke?</p>
 </body>
-</html>
\ No newline at end of file
+</html>
