diff --git a/assert.thy b/Assert.thy
similarity index 99%
rename from assert.thy
rename to Assert.thy
index 4cbca12..ab080b0 100644
--- a/assert.thy
+++ b/Assert.thy
@@ -29,7 +29,7 @@
 
 chapter\<open>An Assertion Framework for Isabelle\<close>
 theory
-  "assert"
+  "Assert"
 imports 
   Main
 keywords
diff --git a/hiding_type_variables.thy b/Hiding_Type_Variables.thy
similarity index 99%
rename from hiding_type_variables.thy
rename to Hiding_Type_Variables.thy
index 7e498dd..51a271c 100644
--- a/hiding_type_variables.thy
+++ b/Hiding_Type_Variables.thy
@@ -30,9 +30,9 @@
 
 chapter\<open>Using Print and Parse Translations for Hiding Type Variables\<close>
 theory
-  "hiding_type_variables"
+  "Hiding_Type_Variables"
 imports 
-  "assert" (* Can be replaced by Main, after removing all assertions. *)
+  "Assert" (* Can be replaced by Main, after removing all assertions. *)
 keywords
     "register_default_tvars"
     "update_default_tvars_mode"::thy_decl
diff --git a/README.md b/README.md
index 13033d4..6e70df2 100644
--- a/README.md
+++ b/README.md
@@ -10,11 +10,11 @@ older versions might be available on a dedicated branch.
 
 ## List of Isabelle Hacks
 
-* [assert.thy](assert.thy) provides a new top level command **assert**
+* [Assert.thy](Assert.thy) provides a new top level command **assert**
   that provides a simple way for specifying assertions that Isabelle
   checks while processing a theory.
 
-* [hiding_type_variables.thy](hiding_type_variables.thy) provides
+* [Hiding_Type_Variables.thy](Hiding_Type_Variables.thy) provides
   print a setup for defining default type variables of type
   constructors. The default type variables can be hidden in output,
   e.g., `('a, 'b, 'c) foo` is shown as `__ foo`. This shorthand
diff --git a/ROOT b/ROOT
index 739a13c..2aee2ca 100644
--- a/ROOT
+++ b/ROOT
@@ -1,5 +1,5 @@
 session "isabelle-hacks" = "HOL" +
   options [document = false]
   theories
-    assert
-    hiding_type_variables
+    Assert
+    Hiding_Type_Variables