Winter is here, and along with it the return of our series History of Thrones. To refresh your memory, History of Thrones examines important historical events and people from the complex and controversial past of Westeros, ones that might tell us something about the story going forward on Game of Thrones. However be warned, we’ll be mining deep into dragonglass and theories, which you might consider spoilers.

You can find all other History of Thrones entries here.

DRAGONSTONE, SEAT OF HOUSE TARGARYEN

King’s Landing might be where Aegon first landed in mainland Westeros, but his conquest of the Seven Kingdoms was launched from the island in Blackwater Bay known as Dragonstone. And while the old seat of House Targaryen suddenly looks ready to once again be the foundation of a dynasty, the White Walkers have long been preparing to turn the realms of men into an empire of the dead. That’s why what lies beneath Dragonstone castle might matter far more than who rules above it.

Roughly two hundred years before their empire was destroyed during the Doom of Valyria (326 years before Aegon’s Conquest), the Valyrian Freehold made the volcanic island their westernmost outpost. Using magic that allowed them to turn stone into liquid, they created the ornate Dragonstone castle (which shares its name with the island). Designed in the shape of dragons and decorated with even more throughout, it sits on the face of the active volcano Dragonmont, which itself gave rise to the island.

Stormy, wet Dragonstone, which smells like sulfur thanks to Dragonmont, is a tough place to live, but despite its rocky terrain it does contain small villages made up of fishermen and some farmers. Its most famous residents though, the Targaryen dragonlords of Valyria, didn’t move there until 200 years after it was originally settled.

The Targaryens were a minor family among the Valyrian dragonlords, but when Daenys Targaryen told her father Lord Aenar that she had a dream foretelling the coming Doom, he moved the entire family to Dragonstone. The other 39 dragonlords thought they were cowards, but Targaryens had a history of prophetic dreams, and Daenys was right. Twelve years later the Doom of Valyria happened, and the Targaryens were all that remained of the once massive empire.

They had five dragons with them when they arrived at Dragonstone, but only one survived—the legendary Balerion. For over a century the Targaryens lived among the Seven Kingdoms, but they were not part of it, nor would it seem they were considered much of a threat to the kings of Westeros.

Eventually though they hatched two dragon eggs, Vhagar and Meraxes, and when they grew big enough the current Lord of Dragonstone, Aegon, and his two sister-wives Visenya and Rhaenys, turned their sights on west. They flew down the Blackwater, arriving in what is now King’s Landing.

After a swift conquest that saw most houses bend the knee rather than be destroyed, Aegon was crowned King of Westeros (though he failed to conquer Dorne, which didn’t officially become part of the Seven Kingdoms until marriages between Houses Targaryen and Martell in 187 AC). Despite ruling from King’s Landing (the Aegonfort preceded the Red Keep), Dragonstone remained the ancestral seat of House Targaryen. The castle would come to fall to the heir to the throne, with the “Prince of Dragonstone” becoming a formal title.

For nearly 300 years the Targaryens ruled Westeros, even after the last dragons died out in 153 AC. But when Robert Baratheon killed Rhaegar Targaryen, and Jaime Lannister put his sword through the Mad King’s back, the dynasty ended. King Robert bestowed Dragonstone to his brother Stannis.

Dragonstone castle is where Stannis both retreated and planned his many futile attacks to take the Iron Throne, over the giant wood carved table of Westeros that Aegon the Conqueror had built. But now on Game of Thrones with Stannis dead and Daenerys having reclaimed her family’s seat, the place where she was born (her epithet Stormborn refers to the terrible storm that took place during her birth on Dragonstone), the focus isn’t on the castle and who rules it. That’s because something far more valuable than a castle can be found there: dragonglass.

Samwell Tarly learned firsthand that dragonglass can kill a White Walker, but the cache of it he found at the Fist of the First Men was lost during the attack at Hardhome. Even prior to going to the Citadel he was looking for anything written about dragonglass, a search he mentioned to Stannis at Castle Black. Stannis told him, “We have it in Dragonstone.”

What he didn’t tell Sam though is they have a lot if it there, under Dragonmont. Tunnels and tunnels of huge deposits of it can be found in boulders and in the walls below Dragonstone. So much so that even though most of it black there is even some red and purple dragonglass.

This is seemingly what Sam found in that book he stole from the Citadel, the one that had the map of Dragonstone with a black spot.

He called it a mountain, but it looks more like an opening, one that is south of the castle. It’s a map that looks very much like this shot of Daenerys arriving at Dragonstone. The location of the castle to the opening of this tunnel is like what Sam saw in that book.

Despite uniting the Seven Kingdoms with a nearly 300-year dynasty, House Targaryen is a relative newcomer to Westeros, where many great houses go back thousands of years. They have no relation to the First Men who fought alongside the Children of the Forest, with their dragonglass weapons, during the Long Night. It’s unlikely the Targaryens ever fully appreciated how priceless their abundant black obsidian was.

So while Dragonstone was the birthplace of a conqueror, and is ready to help launch another one three centuries later, it’s what’s in Dragonstone’s tunnels below that might prove of far more interest to the Seven Kingdoms.

That is as long as the question of who rules Dragonstone castle doesn’t prove more important to the living than who is mining its dragonglass.

What secrets do you think Dragonstone contains? Will the wars of the living prevent them from finding the weapons they need to defeat the dead? Mine our comments section below with your thoughts.

You can find all other History of Thrones entries here.

Images: HBO