Why Game of Thrones fans might cry today if you ask them to 'hold the door'

And why George R.R Martin is a genius...

In Monday night's Game of Thrones episode the tragic meaning behind Hodor's name was finally revealed. The long-time servant of the Stark family, who had gone on the run with Bran when Winterfell was captured, had said nothing other than 'Hodor' since he was a young man. The implication was that he was mentally disabled, but the real reason turned out to be an important link in the plot.

Game of Thrones has been skillfully adapted by its writers David Benioff and D.B Weiss and the books' vast world of characters, cities and landscapes could only be pulled off with the muscle of a big studio like HBO. But at moments like this you have to applaud the materials they're working with.

George R.R Martin introduced Hodor in the very first book, yet it's only now, when his sixth book the Winds of Winter is still in the process of being written, that he's joining up the threads of Hodor's storyline. That's some serious plot-mapping right there.

In this season we've discovered more about Hodor's past via Bran's 'touch the tree root' time-travel skills (not the official term) as a Warg, or someone who can control the actions of others through their minds. In one of Bran's previous visions we discovered a young Hodor was once called Wylis, an articulate young man who showed no signs of mental disability. So what happened?

In last night's episode we found out. While Bran and Meera were being set upon by a pack of suspiciously ork-like wights, Bran travelled back in time to tell younger Hodor that older, future Hodor should 'hold the door' to let them escape.

Bran's mind-control powers appeared to have been so strong that they rendered young Hodor unable to say anything else for the rest of his life, other than 'Hold the door' which blended into 'Hodor'.

Tragically, the reason Hodor had been saying 'Hold the door' for his whole life finally became clear in his dying scene, as the wights hacked through the thick wood and eventually killed him.

Hodor's story was probably one of the most heart-breaking moments in a series that has been riddled with shock deaths and twists. But it also showed off George R.R Martin at his best. Every time we think we've got everything covered off, he goes and peels back another layer of the onion.