diff --git a/bootstrap/typecheck.cc b/bootstrap/typecheck.cc
index 8d2c689..902cf5c 100644
--- a/bootstrap/typecheck.cc
+++ b/bootstrap/typecheck.cc
@@ -6,9 +6,9 @@ namespace xlang {
 std::string typeToString(Type type) {
   switch (type) {
     case Type::Integer:
-      return "int";
+      return "Int";
     case Type::Boolean:
-      return "bool";
+      return "Bool";
     default:
     case Type::Invalid:
       return "<invalid>";
diff --git a/bootstrap/xlang.g4 b/bootstrap/xlang.g4
index 8cb414c..875097c 100644
--- a/bootstrap/xlang.g4
+++ b/bootstrap/xlang.g4
@@ -42,8 +42,8 @@ factor  : Minus factor
         ;
 argumentList  : expr (Comma expr)*;
 
-TypeInteger : 'int';
-TypeBoolean : 'bool';
+TypeInteger : 'Int';
+TypeBoolean : 'Bool';
 If  : 'if';
 Else  : 'else';
 While : 'while';
@@ -88,7 +88,7 @@ Decrement : '=-';
 Comma : ',';
 Semicolon : ';';
 
-Identifier  : [_a-zA-Z][_a-zA-Z0-9]*;
+Identifier  : [a-z][_a-zA-Z0-9]*;
 Integer : [0-9]+;
 
 Comment : '//' ~[\n]* '\n' -> skip;
diff --git a/test/42.x b/test/42.x
index cd4223d..57a8850 100644
--- a/test/42.x
+++ b/test/42.x
@@ -1,3 +1,3 @@
-main() : int {
+main() : Int {
   print 42;
 }
diff --git a/test/fib.x b/test/fib.x
index 9222d17..6d8cd20 100644
--- a/test/fib.x
+++ b/test/fib.x
@@ -1,18 +1,18 @@
-main() : int {
+main() : Int {
   for i := 0; i < 10; i =+ 1 {
     print fib_rec(i);
     print fib_iter(i);
   }
 }
 
-fib_rec(n : int) : int {
+fib_rec(n : Int) : Int {
   if n < 2 {
     return 1;
   }
   return fib_rec(n - 1) + fib_rec(n - 2);
 }
 
-fib_iter(n : int) : int {
+fib_iter(n : Int) : Int {
   x0 := 1;
   x1 := 1;
   for i := 0; i < n; i =+ 1 {
diff --git a/test/sieve.x b/test/sieve.x
index a7a6080..1fb7396 100644
--- a/test/sieve.x
+++ b/test/sieve.x
@@ -1,4 +1,4 @@
-main() : int {
+main() : Int {
   print 2;
   for i := 3; i < 100; i =+ 2 {
     for j := 3; j < i; j =+ 2 {