It’s the literary trick of putting a gun on the wall above a fireplace … If there’s one there, you know it’s going to feature at some future point of the plot.

And far as plot devices go, this one’s impressive.

The wall is 200m tall and 500km long.

It’s built entirely of ice — with the help of a little magic.

It’s 8000 years old.

And it’s regularly-spaced fortifications are supposed to be manned by a devoted band of semi-monastic knights who have dedicated their lives to defending the south.

It took seven seasons of the popular series for this particular plot point to fire.

But the ice wall has been breached — just as almost every wall throughout history eventually failed.

And it represents a calamity far beyond the bickering of local lords.

THE ICE WALL

We have a sketchy outline of the ice wall’s history from George R.R. Martin’s The Cycle of Ice and Fire novels. No doubt, it will feature prominently in HBO’s upcoming ‘prequel’ currently under production.

We’ve been told it was built by a member of the Stark family — Bran the Builder — with the help of the sprite-like Children of the Forest.

We’ve been told it was because of the White Walkers — the near-legendary living dead residing in the icy wastes of northern Westeros — had almost overwhelmed the world in a long winter known as the Long Night.

We’ve been told their strength is somehow related to that strange climatic cycle which delivers summers — and winters — of erratic length.

The ice wall was a line they must not pass.

But this has long since been pushed into the background.

All eyes have been on the deadly power struggles taking place in and around the capital, King’s Landing, and the bid by Princess Daenerys Targaryen to raise an army while in exile overseas.

And the wall itself was being used for a secondary purpose — to hold ragged bands of barbarian ‘Wildlings’ at bay.

But its original purpose came crashing back into relevance at the end of season seven.

DRAGON WIGHT

We know dragons are somehow tied up with the history of the White Walkers. Again, details are sparse.

But clearly they are part of the fire that opposes the Walkers’ ice.

So when one of Daenery’s three dragon ‘children’, Viserion, fell in battle only to be resurrected by the Night King, another vital link in the chain of defences was broken.

And the ice wall itself had nothing in it to resist Viserion’s cold blue fire.

The zombie dragon breached the ice walls’ eastern extremity.

The engineering of Bran the Builder and the magic of the Children of the Forest collapsed in the face of the White Walkers.

Their undead army has been able to cross the line, unopposed.

It’s nothing new.

Throughout history, walls have failed to live up to the expectations placed in them.

France’s Maginot line was quickly overrun in the opening days of World War II.

The Berlin Wall crumbled as what it stood to protect evaporated beneath its shadow.

The Great Wall of China was unable to repel the raiding hordes.

And, most relevantly, the Roman wall of Emperor Hadrian dividing Britain from Scotland repeatedly failed to hold back the mysterious blue barbarian Picts.

THE PAINTED ONES

Hadrian’s Wall is the undisputed inspiration behind George R.R. Martin’s behemoth. Even the map of his land of Westeros looks more than vaguely like the British Isle.

So the Roman wall’s fate may hold clues for the conclusion of Game of Thrones.

Ancient Rome had occupied an uneasy land.

The scenario then was much like Afghanistan is today. The ‘civilised’ Romans constantly had to contend with revolts and roving bands of outlaws.

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After one such particularly irritating uprising in 122AD, the Emperor Hadrian ordered a wall to be built along a rocky outcrop at a narrow point between the North and Irish Seas.

What became known as Hadrian’s Wall ended up being 130km long.

It was built specifically to protect the Roman citizens of Britannia from bands of mystical warriors from the north.

We don’t know what they called themselves. But the Romans dubbed them “Picti” or Picts.

It’s Latin for ‘Painted Ones’.

They covered their bodies in blue paint and tattoos. They fought mostly naked. They were fierce. And their guerrilla raids were more often than not successful.

Essentially, they were the remaining free tribes of Britons that had been pushed back along Rome’s frontier.

A wall was the only way a limited number of Roman Legionaries could hope to hold back such a threat.

It worked. Sort of. Small bands of legionaries could hold out long enough for reinforcements to arrive.

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But not every inch could be constantly watched. Small bands would still slip over, unnoticed.

And sometimes, major Pict attacks would overwhelm one part of the wall or another.

Eventually, the game of thrones being played out among a collapsing Roman Empire brought about the wall’s demise.

Ambitious Roman governors of Britannia stripped it of its legionaries and marched on Rome in a bid to seize the laurel crown.

Left undefended, Hadrian’s Wall was just so much useless rock.

And the Britons took back control of their country. For a time, at least.

WINTER HAS COME

Just as a Bran Stark built the ice wall of Westeros, a Bran Stark helped bring about its demise.

The young cripple was touched by the Night King.

It left an invisible stain on the boy.

Seeking sanctuary in among the roots of an enormous sacred tree, Bran was told of its deadly implications. Another ‘gun on the mantle’.

“He can’t get in,” Brandon told the Three-Eyed Raven ‘watcher’, whose role he was soon to assume.

“He can now,” the Three-Eyed Raven responded. “His mark is on you.”

The magic of the Children of the Forest had been rendered innefectual. And that magic is also key to the fate of the ice wall itself.

The Starks remain the core of the fight against the White Walkers.

But, now, they must defend the already weakened ancestral fortress of Winterfell, guarding the crossroads between north and south.

According to the books, the fortress was built on the hill where the White Walkers were defeated so many thousands of years ago at the end of the Long Night.

We know all the major players in the Game of Thrones are rushing north — except Queen Cersei. She’s alone, with her army, at King’s Landing.

And the Stark family’s fortress is the place the next big fight with the White Walkers must be.

Will Winterfell fall, as did the ice wall?

We know the show’s producers spent a record 55 days filming an epic battle scene in terrain similar to what Winterfell’s is supposed to be.

And the official Season 8 teaser ominously shows a frosty cloud creeping over a map of Westeros, consuming the Targaryan dragn and Stark direwolf symbols and the city of Winterfell itself — as a torrent of fire rages northward over the Lannister lion and King’s Landing.

The guns on the mantlepiece have been fired. We have few clues remaining as to the outcome of The Game of Thrones. But, rest assured, it will be hiding in plain sight.

@JamieSeidelNews