It's high time we started talking about Euron Greyjoy's 1,000 ships.

In all the excitement/rage surrounding Ed Sheeran's cameo and the general furore that comes with any new Game of Thrones season, it's a storyline that seems to have slipped through the cracks somehow.

Ever since the end of Season 6, though, it's been bugging me.

First, let's have a very quick recap of what Euron was up to the last time we saw him, prior to his sassy appearance in last Sunday's Season 7 premiere.

Image: hbo/mashable composite

Yep: he'd just had his "best ships" pinched by Theon and Yara, and was casually encouraging his fellow Iron Islanders to build him "a thousand" more.

Well, flash-forward to the start of Season 7, and it looks like Euron got his wish.

Here's the new-look hipster King of the Iron Islands, standing before Cersei and waffling on about how he's the "greatest captain of the 14 seas" and his boats are basically the best thing ever, etc. etc.

Total hipster. Image: hbo

The thing is, he's not just boasting: we can see he does indeed have a ton of shiny new boats from the shot of them all sailing into King's Landing. He even goes one step further and confirms the number itself.

"So here I am, with 1,000 ships," Euron grins, "and two good hands."

It's a nice line, but the thing that's bugging me is this: How the sweet hell did Euron actually manage to build 1,000 ships so quickly? Especially seeing as he lives on a place that he himself describes as "nothing but rocks and bird shit"?

I did a bit of digging and spoke to some historians and ship-building experts to find out if it's actually possible.

What did IRL medieval kings do when they needed ships?

Game of Thrones is obviously a fantasy show, but that doesn't mean it's totally unanchored from reality.

"Ships were the largest, most complex and most expensive machines that existed at this time."

"My sense is that Game of Thrones is set in a quasi medieval world with technology and a social structure that's roughly what you'd find in 13th/14th century Europe," Dr Evan Jones, a specialist in maritime history at the University of Bristol, told Mashable.

Jones explained that during this period there were some examples of big fleets being gathered.

"Henry V's Harfleur Campaign of 1415 required 1,500 ships to carry his invasion army from England to France," he explained. "However, the vast majority of these ships were hired from the existing merchant marine."

This is the key difference: Henry V's 1,500 ships weren't all built from scratch.

"That was pretty much standard practice," Jones added. "Nobody in their right mind would build a fleet if they could possibly hire them. That's because ships were the largest, most complex, and most expensive machines that existed at this time."

So how long does it actually take to build a ship?

To get the low-down on exactly how long it might take to build a ship of the type Euron's men sail, I spoke to writer and historian Dr Ian Friel — he recently wrote a book all about the medieval fleet Jones referred to (Henry V's Navy — The Sea Road to Agincourt and Conquest 1413 - 1422), and he knows a thing or two about medieval military ship-building.

"The ship that you cite [the one seen leading Euron's procession in Season 7, Episode 1] looks to combine aspects of vessels dating between the 1300s and 1500s, with some elements that are purely imaginary," Friel explained. "At a very rough guess, in medieval English terms it would be a vessel of about 500 tons."

The closest real-life example to this, Friel explained, might be one of King Henry V's "great ships" called the Trinity Royal. Like the big ship we see leading Euron's fleet, it too was a 500-tonner.

"Construction of the Trinity Royal started in November 1413, at Greenwich, and it finally left its building dock on the Thames in February 1415, so it took around 15 months to build," said Friel.

"I would guess that the building period for Greyjoy’s big ship would be similar."

Okay, so that's the first figure to keep in mind: 15 months to build one of Euron's biggest ships.

Image: hbo/mashable composite

How many people would be needed to build this type of ship?

The building team for a 500-ton ship, according to Friel, would be between 30 and 50 shipwrights or more.

"However, other craftsmen and workers would also be involved, such as blacksmiths to make nails and other ironwork, caulkers to seal the gaps between planks, sailmakers, labourers and even people employed to pick up small bits of leftover timber littering the building site," he said.

"The total size of the project team would probably be 50+, though not all would be working at the same time.

"Building a fleet of 1,000 vessels in a short time would require tens of thousands of workers."

So how many trees would you need for a 1,000-ship fleet?

Historians don't know the total number of trees felled to build the 500-ton Trinity Royal, Friel explained, but they do know it took 3,900 trees to build the 1,400-ton Grace Dieu — the largest of Henry V's fleet.

"Even this doesn’t account for all the timber used, because hundreds of other pieces of wood were also used for the work, plus boards and other items bought readymade," he continued. "However, the 3,900 number gives a rough rule-of-thumb figure of just under three trees felled per ton of ship.

"Taking three trees per ton as a minimum (to allow for the other timbers that weren't complete trees), this would equate to around 1,500 trees being needed to make a 500-ton ship like the Trinity Royal – and perhaps also Greyjoy’s ship."

The thing is, not every ship in the fleet is going to be 500 tons. There are variety of sizes needed to perform different tasks — fighting, reconnaissance, storage, patrolling, etc. — and Friel explained the average weight of a ship in Henry V's fleet was probably more like 250 tons.

So, taking an average of three trees for each ton of ship, Friel calculated:

Image: Shutterstock/rtem/mashable composite

Yep: 750,000 trees.

"The National Forest estimates that a mature woodland would have between 250 to 500 trees per hectare," Friel continued. "Taking the higher figure, a hectare would build about 166 tons of medieval ship.

"On this basis, a total of 250,000 hectares of forest would be needed to build the 1,000-ship fleet, or 2,500 sq km. That’s equivalent to 139 Epping Forests or a wood that is one-and-a-half times bigger than Greater London."

These are tentative figures, Friel stressed, but they do give a sense of the scale of ecological disaster building 1,000 wooden ships in a short space of time would cause.

"If the Iron Islands were really as rocky and desolate as Greyjoy says, it sounds unlikely that he would be able to find enough timber for a 1,000-ship fleet, besides all the workers, iron, rope, canvas and other materials needed," said Friel.

Conclusion

Image: hbo/mashable composite

Okay, so there are a few caveats to this whole argument worth mentioning:

1) We don't know exactly how much time has passed between Euron's speech at the end of Season 6 and his impressive arrival in King's Landing at the start of Season 7.

2) We don't know that he actually built his fleet of 1,000 ships. Theon and Yara apparently only stole his "best ships", after all, so he probably had a decent few left over. And being the ruthless, cut-throat type of guy that he is there's a chance some of his fleet may be stolen.

Both of these are valid points that I can't really counter. There's no way of telling exactly how much time passes in the Game of Thrones world, and the acquisition of Euron's 1,000-strong fleet happens off-screen.

But still. Given the figures above, Euron's "build me a thousand ships" speech starts to look more and more ridiculous. At a push it might be believable to say a couple of years have passed between Seasons 6 and 7 (enough time to allow for the 15-month ship building period + time for Euron to stock up and sail to King's Landing), and I guess it's feasible that he could have forced tens of thousands of people to build for him.

The sheer scale of resources needed is what makes the whole thing unbelievable, though. Not only would you need 750,000 trees, but you'd also need enough construction areas to simultaneously build 1,000 vessels.

"Much would depend on how many shipyards you had available," Jones said. "Not a 'thousand', I suspect..."

Ultimately, it's a fault of the script. Euron didn't need to make that speech. He could have hinted at stealing ships as well as building them, or he could have implied he had a bunch left over and only needed to replace the ones Theon stole.

He didn't, though. He specifically says "build me a thousand ships" at the end of Season 6, and then he repeats that exact number at the start of Season 7.

For a man with little besides "rocks and bird shit" at his disposal, it's one hell of a stretch.