The theory was born when Sam first entered the Citadel, the capital of the Maesters. A large astrolabe can be seen hanging from the roof of the library...
Which looks a lot like this thing that appears on the opening titles of every episode...
And a conversation that Sam had with Archmaester Marwyn in last night's episode only adds fuel to the fire.
"If you're going to write histories, Tarly, you have to do the research," the Archmaester lectures Sam. "If you want people to read your histories, you need a bit of style. I'm not writing, A Chronicle of the Wars of Following the Death of King Robert I so it can sit on a shelf unread.'"
But Sam isn't very happy with that title, and has a look of disgust on his face.
The Archmaester retorts:
"What? You don't like the title? What would you call it then?"
To which Sam says:
"Mm, possibly something a bit more poetic?"
The Archmaester quickly dismisses the idea:
"We're not poets, Tarly."
Well, we know we're not reading A Chronicle of the Wars of Following the Death of King Robert I. So what's a more poetic alternative? A Game of Thrones or maybe even A Song of Ice and Fire. MIND. BLOWN.
In fact, the theory is so convincing that John Bradley, the actor who plays Sam, thinks it's true.
"One theory is that what we're seeing now and how we're experiencing Game of Thrones is Sam telling the story of Game of Thrones," Bradley told The Hollywood Reporter in July 2016. "If you take the logic of the story now, the story of Westeros and the story of the battle for the Iron Throne, it would be a book in that library. The visual motif of that is you're about to be told a story — the sense of an idea of being told a story, and people gaining that knowledge, the way Sam is absorbing knowledge in the library."
We bet you never thought Samwell Tarly would be the most important character in Game of Thrones.