integratable php blog API for existing site?

I'm inheriting a php project of a complete website. It's currently static; the owner just wants a blog on the front page to keep things fres开发者_Python百科h. Is there a mature PHP blog software out there that I can make a few calls to and have a blog up and running on their front page, without having to convert their entire existing site to a blog or CMS software?

That's one of the use cases for Serendipity. It has a configuration option specifically for that. So unlike Wordpress you don't need to hack it. It's not as featureful and a somewhat bloated package, but has a far better security track record.

http://www.s9y.org/123.html <- embedding howto