This page is still being populated with resources. Here are a few to start, but keep checking back as this list grows!
Here’s one of our favourite blogs that regularly updates on the subject:
https://classicalassociationni.wordpress.com/category/blog/game-of-thrones-and-ancient-history/
For reference, here’s the Songs of Fire and Ice Wikipedia:
http://awoiaf.westeros.org/index.php/Main_Page