I've been asked to add a CMS to an existing Cake PHP driven site. Cake PHP doesn't appear to drive much of the site outside of URL structure, templates and forms (there is no content management).

The client doesn't want to convert the entire site to ExpressionEngine all at once due to cost constraints.

I'm guessing CakePHP probably routes everything through index.php like EE does, so I'm wondering if it's possible to run them side by side? 

I suppose on approach would be to run the ExpressionEngine portion on a sub domain. Are there any other approaches?

Thanks,

Anson