Something wrong with Category.php?

I’m using a custom version of category.php. When I use it at a template for a page, and then visit that page, it lists all the categories, but, if I click on one, it loads the right URL, but it’s the same content (the list of categories) rather than all the posts, as it should be. Here’s my category.php:

<?php
/*
Template Name: Category
*/
?>
<?php get_header(); ?>
<h1 class="page">Archives by Topic</h1>
<ul class="archive">
	<?php wp_list_categories( 'title_li=' ); ?>
</ul>
<?php get_footer(); ?>

Am I doing something wrong?