Hereby a command is given in the name of the Equestrian Diarchy to all whom it may concern: to allow the bearer (Professor Silver Compass) to pass freely without let or hindrance, to afford the bearer such assistance as is necessary and to ensure his safe return.

As the train chugged along, Silver Compass read the letter again, even though he knew it by heart now. It was repeated in Equestrian and Griffonian, and followed by a large official seal. He was fairly certain he was the first pony to receive such a letter. They were all under Celestia’s protection of course, no matter where in Equus they went, but it was still comforting to see it in black and white.

What was strange is that the Griffonian Democratic Republic had insisted on him having it. They were nothing but eager to have him, but if he were a visiting academic he must have something stating under which state’s protection he was. No exceptions. A strange quirk, but at least having it had made the Imperial Guards at the airship dock politer. A lot politer.

He was just glad two weeks of airship travel were at an end. Two weeks crossing the Eastern Ocean was more than enough time to question his life-choices and how exactly he had ended up in his situation.

Two and half weeks ago he had no idea he was about to embark. He had been at home in Canterlot, reading some papers on Starswirl’s unsolved theorem—he scribbled in the margin of a book with a claim to have a proof, but none was ever found or published—when there had been a knock on his door.

He went to the door, impatient with whoever had disturbed him to sell a vacuum cleaner or something similarly useless. Instead of a salespony he found a squad of Royal Guards.

“I am Sergeant Bright Lance,” the guard in front said. “Are you Professor Silver Compass?”

“Your presence is requested at the palace for a vital diplomatic matter. Will you attend?” asked Bright Lance. He had a short, sharp way of talking, like every guard: their speech was as identical as their appearance.

“Yes.” For a moment he had feared there was an emergency evacuation or he had been accidentally involved in some crime. If it was a diplomatic matter, it was probably related to the international journal he edited. The Griffon Queen was notoriously sensitive these days; perhaps he had accidentally offended her and now had to make a perfunctory apology to the ambassador.

He walked the route often enough; the university he lectured at was very close to it. He had, however, never been escorted by eight Royal Guards when walking the route. They were not marching, exactly. But the way they walked was lockstep and fast. He was falling behind and started cantering to keep up with them.

The streets were not very full, and no one paid them much attention. Royal Guards were a common sight, after all. It did also not behoove Canterlot ponies to stare at sights, like common ponies would.

Soon, they were at the palace. There was a brief halt at the gate when Bright Lance explained who they were to the guard at the gate, but quickly they went on.

He could not help but look around at the inside. He had not been in the palace in a long time, and it was every bit as beautiful as he remembered. As they marched through the halls he noticed again an illuminated map hanging above the stairway to the diplomacy suites. He had seen it several times and always found it very beautiful. He was admiring a painting with a scene from the Crystal Empire when he noticed all the decorations were completely unfamiliar to him.

“Wait, the diplomacy suites are back there!” he said. At this point he was starting to realize he would have to make more than a perfunctory apology to a diplomat. He knew they usually just sent a Royal Guard with a scroll when he was needed at the palace. A polite scroll, not a squad of guards to march him to the palace immediately.
“We are going to the throne room,” said Bright Lance. Silver Compass felt he had forgotten his stomach at home.

“....” Silver Compass had fainted. The two guards closest to him shrugged. Each lowered a head and took one of Silver Compass forelegs over their withers. They started dragging him to the throne room. This was a fairly normal occurrence after all.

“Please do not be alarmed, my little pony,” said a kind, warm voice that he was sure he had heard before. He felt uncomfortable. His legs were bent at unnatural angle and his barrel was laying on the cold floor. He opened an eye and saw a large white leg in a golden shoe.

“Your majesty.. ies!” he said, alarmed and correcting himself when he noticed Luna. He scrambled up. He realized he hadn’t bowed and knelt down again. His balance was however not fully recovered yet, and he fell over. Celestia sat down while he stood up again, more carefully. He was in the throne room. The actual throne room. Luna was on a throne next to Celestia, and both were looking at him as well as a variety of guards and servants.

“I have a letter for you,” Celestia said levitating a piece of paper to him, “it is an invitation to take part in a round-table discussion of mathematics in Talon’s End University.”

He took a moment to concentrate on the strangeness of the letter, because the Princess playing postmare was currently too confusing to contemplate. It looked more like a page from a book than a letter. It was pure white with neat printed black letters. But, it was clearly a letter. It had his name on it, right at the top. Had whoever sent it gone to the great trouble of assembling an entire box of type and setting up a printing press just to make one letter look nice?

“There is a reason why it did not come through your letterbox,” Celestia said. “The University has been trying to invite you for many years. We were convinced to intervene in the negotiations with Queen Odilla to allow you passage.”

The room was very large and open, but Silver Compass still felt as if the walls were closing in. He focused forward, trying not to faint.

“Queen Odilla of the Griffon Empire,” Celestia added helpfully. “Are you familiar with the former province of Talon’s End and the current situation?”

“No, your majesty,” said Silver Compass, “I remember there was a bit of a disturbance there… many years ago?”

“Indeed!” said Luna loudly, “the Griffons reinvented an old craft and brought forth a portal to a new world! A most magnificent achievement! And being such beings as they are, they immediately became embroiled in a bloody war with its inhabitants.”

“We intervened and negotiated a peace settlement,” said Celestia. “As part of the settlement, the province of Talon’s End—where the portal is—would become a separate state, subject to the leadership of the citizens of the other world. It is now called the ‘Griffonian Democratic Republic’.”

“A new world!” exclaimed Silver Compass, “Why did nopony hear about it?”

“Queen Odilla took the peace agreement poorly. She ordered every border sealed around the province. The inhabitants are not allowed in her empire. Not even her former Griffon subjects in the province are allowed passage. She also ordered any communication from and to the province burned or blocked. This of course means the new world’s inhabitants can not visit the other nations of our world.”

“Brought by us,” said Luna, “on our way back from a diplomatic visit. A most successful visit, we might add!”

“We, meaning Luna and I, would consider it a personal favour if you would accept this invitation and attend this discussion,” Celestia finished for Luna.

“Well, subject?” asked Luna not letting him have the minute, “What sayest thou?”

He understood well enough that he had become embroiled in a complicated game of politics. He was not sure why they had chosen him. The only thing that could have brought him to their attention was that he was the editor for the international journal of mathematics. But still, why him specifically? If they wanted internationally minded professors, there were many. He dined with the Chair of International Languages and Cultures at Canterlot University often enough.

He could think of no real reason why it was him sitting in this quite uncomfortable train, flanked by a Unicorn Guard and a Night Guard staring into a very surly Griffon administrator’s face.

Not that he wasn’t eager to go, even now. The letter, once he had finally read it, had been a standard and bland invite for a discussion of the state of the art of Equestrian mathematics and the possibilities of contributing to each other’s knowledge. It was printed oddly, but that could just be tradition. However, at the bottom they had included a list of numbers. He would have come all this way, alone, just to ask them about that list if he had gotten that letter in his letterbox.

2 - 3 - 5 - 7 - 13 - 17 - 19 - 31 - 61 - 89 - 107 - 127 - 521 - 607 - 1279 - 2203 - 2281 - 3217 - 4253 - 4423 - 9689 - 9941 - 11213 - 19937 - 21701 - 23209 - 44497 - 86243 - 110503 - 132049 - 216091 - 756839 - 859433 - 1257787 - 1398269 - 2976221 - 3021377 - 6972593 - 13466917 - 20996011 - 24036583 - 25964951 - 30402457 - 32582657

It was obviously the Mersenne Primes. At least the first dozen were. The rest were implied to be, by their inclusion in the list. But even to prove 2¹²⁷ - 1 a prime number had been a massive effort. He could not imagine the effort to prove 2³²⁵⁸²⁶⁵⁷ - 1 prime. To calculate with anything resembling traditional means would wear down every piece of chalk in Equestria. Just writing it down as a number would require a massive hall of endless chalkboards, or several thick books

He was undoubtedly the first pony, ever, to know that 2⁵²¹ - 1 is one of the Mersenne Primes. He could hardly suppress a giggle of excitement.

“It is not appropriate to laugh in the Silent Province,” said the administrator, who had escorted them on the final train. He had not given his name to them, as a sign of disapproval of their mission. “A hundred thousand died here.”

“Look,” the administrator said, pointing a talon at the window. Silver Compass had not bothered to look out the windows much this train ride. He was too busy worrying.

He looked out the window and saw lush green grass and shrubs, growing tangled through the blackened ruins of a city, through which the train was passing. There wasn’t a single building standing, just endless ruined remnants. All of it had fallen at an angle, pointing back to where the train had come from.

“They did this. A hurricane of fire,” the administrator continued. “One moment it was a bustling city and the next it was torn apart. They poisoned the ruins somehow; we can not even rebuild the city. All who lingered here grew very ill. Just clearing the tracks for this train was an incredible effort.”

“No,” said the administrator shortly. “The province. So, please, show respect. If you have any left, after betraying our world to consort with theirs. You being here is an insult. They destroy one province, enslave another and you come over to make polite conversation with them.”

Silver Compass sat in silence the rest of the trip. Magic always left traces and great magical battles could scar huge areas, like the Everfree Forest. Or completely throw them out of time, like the Crystal Empire. Whatever magical artifacts or ruling entity that guarded the realm the Griffons had found certainly was not subtle or very precise. He was curious, but he did not feel it would be polite to ask for details.

Silver Compass paused, even though he had been told not to linger. The final part of his journey was on hooves: a five mile walk from the Imperial fortress. If he looked backwards again he could see it looming behind him, thick stone enclosed in an air-tight forcefield. If he had cared to look left or right in the far distance he could have seen the tiny spheres of the subsequent fortresses in the chain that surrounded the entire province.

He was however looking at his destination. There was a massive statue of a griffon in bright copper, a mountain ridge on either side. It was standing with a talon held in front of it, pointed directly at the fortress he had come from. Half a broken manacle hung from its wrist. It was fierce and accusing; with raised wings and narrowed eyes.

His destination was just underneath the statue. It looked like something out of the Crystal Empire, shining brightly like a faceted jewel. He had been told it housed the portal.

He saw no welcome banners or anything outside, just a doorway in a shining wall. From this view it seemed deserted. Was he supposed to just walk in? Did he need to present his letter to some hidden defense before he would be allowed through?

“Where are the guards?” he asked. He did not wish to be mistaken for a spy, by whatever defence the Republic had put up.

“We could never see them,” said Bright Lance, one of the guards he had been assigned, “but they must be there. Five years ago a small party of mercenaries tried to attack the building. Of course Queen Odilla denied all involvement. They did not make it halfway across.”

“Queen Odilla?” asked Silver Compass, trying to place the name. “The Griffon Queen?”

“I see,” said Silver Compass, not feeling reassured at all. “Was that true about the Silent Province?”

“Oh,”. The grass under his hooves was soft and springy; all in all it should have been a pleasant walk. But the closer he came to the building, the more the statue loomed menacingly. He could feel a horde of invisible eyes on him, watching from who knew where.

He was an academic, used more to a sedentary lifestyle. Five mile walks were not part of his daily routine, and it took him a few hours including breaks. However, he still came to the front of the building much sooner than he would have liked.

Two griffons had walked out to meet him. They were dressed bizarrely, even to someone who was used to Canterlot fashions. Their entire bodies were covered by a dark blue suit of sorts, and they wore blue caps. However, unlike what one would expect from such a ludicrously formal choice of clothes everything was simplistic and undecorated. A few trimmings at the seams, some symbols here and there were the only variation from the solid blue colour. He could also see no weapons.

“Silver Compass, a pleasure to meet you. I am officer Asta Elofsdaughter and this is my colleague officer Hagen Gunnarson,” said Asta. Her introduction had been elegant Griffonian, except for officer which was not a word he knew. It was not Griffonian, judging by the weird sounds in it that Asta could not quite pronounce. He could of course not judge anyone on that, due to not having a beak he had to click his teeth on most of the Griffonian consonants.

Silver Compass sighed. It seemed he was not yet done being a parcel passed around between various officials.

They walked through the large door in the wall of glass. Inside was a large hall, with a marble floor. The light shone in strange patterns on it. The hall was however, almost entirely empty. There was a large circular desk in the middle, but there was nopony attending to it. All things considered, the eerie emptiness that marked his approach was still present.

A thing lurched out of a hallway at the back, startling him badly. There was no other way to describe how it moved. It was bipedal, but its way of walking was nothing like a Minotaur’s shuffle. It looked like it was constantly in the process of falling over and just catching itself. Silver Compass was about to try and hide behind his guards when it spoke.

“Welcome,” it said, “I’m called Charles Campbell head of the diplomatic corps of the GDR.” He spoke Griffonian, or at least made an excellent effort. He also used his teeth instead of a beak on the more difficult consonants. For his name however, he had spoken in whatever language was his own. Silver Compass could identify maybe half of the sounds, and only then from the many languages he spoke. It included at least one bizarre tongue trilling noise he had thought was unique to the Zebras.

The alien name just added to its alien appearance. It was also dressed as formally as the other guards; the only parts of its body he could see were its hands and face, both of which were disturbingly without fur or feathers. It was, however, dressed less simply than the griffon guards, wearing a layered upper body covering, a curious wrist bracelet with a clock face, and a bright cheerful tie that would not have looked out of place at the Grand Galloping Gala.

His pondering on appearances was disturbed when he realized he was being handed something. A small card. Somewhat confused, he took it with his front hoof. On it was his face — an excellent photo too — and name in Griffonian letters. Not sure what to do with it, he put it in his satchel.

“Please do not lose that,” continued Charles, “if you do, please report it to the nearest police officer as soon as you can. It is your proof of identity. You will need it to enter at the gates and do various other things. Your guards should already have theirs.”

“Yes, please… “ said Charles, he started to make a gesture with his front limbs. The meaning Silver Compass could guess at.

They walked quickly. Charles’ strange gait was surprisingly fast. They walked past the empty reception desk and towards a doorway in the back. When they went through it he realized what was making everything seem weird: every ceiling and doorway was about twice as high and twice as broad as he was used to.

After a short walk through a hallway that was surprisingly utilitarian, at least considering the gleaming outside of the building. It had a plain white ceiling and walls and a dark tiled floor of some sort. They turned left into another hall.

The view there was not so utilitarian. They arrived at a railing, with a circular walkway going both left and right. Looking down, he saw many other walkways on lower floors and finally a circular floor. Escalators, like in Manehattan, connected the various levels.

Griffons were everywhere; oddly, not a single one flew. Here and there one of the strange creatures lurched about. Everyone was wearing a ridiculous amount of clothes. He had never seen Griffons wearing anything more than ceremonial or combat armour before, but almost all the clothes fit well and were obviously made for the Griffonian shape.

Bright Lance politely nudged him, and pointed to their guide. He was quickly moving ahead of them, and they had to hurry to catch up.

“It is the only connection to Earth,” Charles said. “Even for what amounts to a large city-state a single small port for every piece of cargo and every passenger is a tight fit. The scheduling has posed some unique challenges. Unfortunately we’ve been told opening a second portal is utterly impossible while this one is active.”

While highly informative, this was not exactly what he had meant to ask. However, he could not bring himself to rephrase the question.

“Do you think it would be possible to open a second portal?” Charles asked, in a manner that seemed to be casual.

“I… wouldn’t know, “ said Silver Compass. He tapped his forehead meaningfully. Charles only seemed confused by the gesture though, so he explained it.

“Oh. I recall with the Griffons there is also a genetic predisposition, but nothing like a caste system.”

Silver Compass had not fully understood the sentence; it used a lot of specific words in what was his third language. But he could not help feeling vaguely insulted.

“Left here, please,” said Charles. He had been leading them around their current landing, but they had come to a nondescript door against the wall. He was unfamiliar with the style of door handle: it was a long pointed thing with a metal slot underneath instead of a normal keyhole. It was some kind of keyhole though, because Charles stuck a flat white key into it, which made a small light on it blink green and click open.

The door opened on a sight that was more than a little strange. A wall of what looked like nothing so much as wire cages. They reached from floor to ceiling with no room between them. Each looked big enough to hold a single griffon, or big enough to hold him with room to spare. They were all empty, with their doors swung open. Through the wires he could vaguely see another door in a wall on the other side.

“This is the diplomatic entrance to the station,” Charles said. “You will be taking the maglev to the center. There you will be met by a person from the hotel. You have to pass through border control first. This is a priority entrance, which is good because otherwise you’d be in a very long queue.”

“Oh.” Silver Compass was sick of trains. Ever since he had landed in the Griffon Empire he had taken a series of trains. Initially they had been up to Equestrian standards. But as he came closer to edge of the Griffon Empire they had become less comfortable inside and had gone over progressively worse track. He was not looking forward to another long bumpy train ride with unscheduled delays.

“Passport control. Just use your card. They are immune to illusion spells. Once through, go through the door in front. I will wait here until you are through in case you have any problems. Goodbye!”

Nervously he approached the metal cages. His guards seemed to be familiar with them; they both walked into one and pulled shut the wire door behind them. He walked into a third, empty box. A very large sign with utterly alien script covered most of the front wall. Underneath was a black shiny rectangle.

Not sure what to do, he attempted to read the sign. There were a dozen of scripts which seemed to have little in common except being entirely unreadable. He was glad to see that in the bottom corner was Griffonian. However, just above it he saw something even better, Canterlot Equestrian. It politely instructed him to close the gate behind him.

He could have guessed that but didn’t want to try until he was sure. He grabbed the gate at its protruding lower crossbar with his hoof, which was somewhat uncomfortable. There was a round knob, but he could not grip it easily, as it was too tall for him. The gate closed easily enough, but with a very final buzzing noise. He could no longer see out easily. He pushed it, and it did not yield in the slightest.

He was trapped. He looked back to the sign quickly and realized there was a second part. ‘Please touch your identity card to the white dot or slide your passport through the slot.” He could not read one of the words, it looked like a phonetic loanword but of what he could not guess. He could however guess what kind of card an identity card was. He retrieved it from his satchel and found the white dot, just underneath the black rectangle.

“Welcome to the automated passport control system!” a happy cheerful voice sounded out of absolutely nowhere, in perfect Griffonian. Letters were appearing on the black rectangle, spelling out what the voice said. “We detect that this is your first visit, is that correct?”

“I could not understand that. Please repeat loudly and clearly,” the voice continued, still bright and cheerful.

“Thank you! Please look directly forward, to facilitate initial registration.”

“Thank you! You are now registered! You are entering on a special diplomatic visa, is that correct?”

“Yes…” he said, not sure what a visa was, but fairly certain he was entering in a special and diplomatic way.

“I could not understand that. Please repeat loudly and clearly,” the voice said, in exactly the same way it had the first time.

There was another buzzing noise and the screen swung away to the side. The way was now clear to the door he saw from the other side. And, he was thankful, both of the guards were waiting for him.

“Some kind of enchanted gate. Not a very good one,” said Bright Lance. “Let us go. We don’t know when this train will leave.” He pointed to the door behind them, which Silver Compass realized was not a normal door at all. They had stepped onto what looked like small enclosed railway platform. It was a door to a train carriage, presumably.

They walked to the door easily enough. However, he could see no knob or handle or anything that would open it. He turned to ask Bright Lance what to do, but Bright Lance was looking at him.

The door opened with a hissing noise, startling them both. Night Wing took his hoof off of the small button on the side of the door. Saying nothing, he walked into the carriage. They followed him.

The carriage looked surprisingly normal. Sure, the tables and windows were too high and the benches around them too narrow but all in all it was a typical train carriage. There was another one of the black reflective things hanging on the wall, but it showed nothing. He could see a door leading to the rest of the train, but he guessed this carriage was reserved for them. They took a seat around one of the tables. Both of the windows showed nothing but grey wall.

“The only sentient inhabitants of the other world, ‘Earth’. They call themselves ‘humans’. You get used to them walking about after a while. Their balance is very good; they are surprisingly stable so upright. There’s very little difference visually between humans...”

Bright Lance had started explaining how humans mostly had a small range of shadings of brown as their only colours, but was interrupted by a loud hissing noise and another voice.

“Gah! Why does everything move by itself here?” Silver Compass asked, frustrated. “And why the mysterious voices!? Are they so proud of how they managed to get everything to move without showing a bit of enchantment that they have to announce it to the world?”

“We do not think they are able to enchant things or even use basic levitation,” said Bright Lance, “at least, we have never seen anything leaking magic, and that is difficult to conceal. Whatever they use as a come-to-life substitute is very effective and invisible. There are a lot of Griffon enchantments in the various old buildings, but none in this new building.”

“Gah,” Silver Compass said, more frustrated. Why had he not been accompanied by a full faculty? Undoubtedly the Chair of International Languages and Culture would have give his horn to see the multi-lingual sign. And a Mage, well, a Mage more inclined to academic study than a Unicorn Guard, would probably at least be willing to share his confusion.

“Look,” said Night Wing, pointing at the window with a hoof. Silver Compass realized this was the first word he had heard from him in two and half weeks. He would have said something, but he looked out the window.

The landscape was a blur. All but the distant mountain range was impossible to see properly. The start of the motion and acceleration had been so smooth he had even not noticed it. They were going fast. Certainly faster than he had ever gone in his life before. There was also a subtle pressure, now that he was paying attention, they were still accelerating. It was by far the smoothest train ride Silver Compass had ever had.

An Academic Visit

by RustPony

An Unexpected Invitation