I have a simple site (header.php, footer.php and some content sites in between) and I want to include Wordpress as one of them. I install it and it works as domainname.com/blog, but I am wondering if I can get it to work under regular header.php, just like with other pages (Home, Services, Resources, Blog, Contact)
I am using something like this:

<?php
$subtitle = "Media Services";
include("header.php");
?>

When I add the following code, it does not load anything,

include("blog/wp-blog-header.php");

but a test file like test.php (with echo "This is test etc..") works with the same pathname.

Does anybody know what am I doing wrong. I basically want to have blog under the header here Belerose Media Blog instead of Belerose Media Research & Entertainment Blog | Just another WordPress site

Thank you.