This reference to the Game of Thrones title sequence in the season 6 finale could change everything

If you watched the season six finale this week you may just have spotted something that looked very similar to what we see in the title sequence. As an awestruck Sam makes his way into the vast library at the Citadel, hanging from the ceiling is this device...

At first glance it looks as if its function is to reflect sunlight from the window high above around the room via those mirrors – and that's right, because the Maesters who use and maintain the library would never risk having candles anywhere near their precious books.

But on closer inspection it – and another similar contraption in the foreground, below – are also very reminiscent of the winding bands of metal we see in the opening credits, with the sun in the middle the glowing ball of light.

So could the device have a second function? Well, yes, it's called an astrolabe – or more accurately an armillary sphere. And you can actually buy one...

So what does it do? Well, an amillary sphere is a model constructed from revolving hoops representing celestial bodies, their lines of longitude and latitude and so on, usually with the sun or the earth at its centre.

It was used to track the movement of the stars and planets and could therefore also show the changing of the seasons. Given that the Maesters at the Citadel determine when the long seasons of Westeros officially begin and end – sending out white ravens to share the news – it seems likely they are using the armillary globe to help make those decisions.

Of course, the blades of the astrolabe also show the history of Westeros, in terms of the ebb and flow of its continual power struggle (in many ways it is a record of "the wheel" Daenerys speaks of breaking: “Lannister, Baratheon, Stark, Tyrell – they’re all just spokes on a wheel. This one’s on top and that one’s on top and on and on it spins, crushing those on the ground... I’m not going to stop the wheel. I’m going to break the wheel.”)

And one intriguing theory suggests that the astrolabe and the changing map of Westeros we see each week actually represent the unfolding of a story being told to us by one of the Maesters – quite possibly Sam himself.

Consider the following...

When Sam first arrives at the Citadel, he is greeted by a Maester using a distinctive pair of glasses to read the texts in front of him. Here are those glasses...

And here are some views of the map seen in the opening credits through lenses very like those glasses.

So perhaps the map is being observed, and gradually altered, by a Maester reading the story as it progresses.

Remember, the Three-Eyed Raven told Bran, "The past is already written. The ink is dry". Was that perhaps more literal than we thought – another hint that the events of a Song of Ice and Fire have already taken place and been written down?

If so, could the very last scene of Game of Thrones be old Sam looking up from a book after finishing his tale?

And could this be what he looks like, decades later...?