Pre-Celestia’s Reign was marked with countless wars in Equestria’s history. There were scant years when Equestria wasn’t fighting some foe or another. This, while a travesty, has sharpened Equestria’s army to the point of near perfection when it comes to warfare. Equestria knows and has tried at one point or another, every method of warfare available. Tried and perfected it. They  had to in order to survive almost constant war.

However, in the thousand years that Celestia has taken the role of sole monarch of Equestria, there has been a marked drop of wars plaguing the nation and the world at large. That said, while there has been a marked drop, there is an easier point of reference to point out the number of significant wars that Equestria has fought in the last thousand years. This list does not include single local battles or naval conflicts. All of them were substantial land/naval wars that occurred over long periods of time and affected Equestria’s history.

1: The Twilight War 1005-991

Contrary to common belief, the war did not end automatically after Nightmare Moon's defeat. It is true that the armies of Nightmare did break down since Nightmare Moon was the leading figure for their cult and was more or less in charge of every operation and made the final plans. This of course caused a meltdown of her loyalists, with some fleeing or even fighting amongst each other for control. The first nine years of Celestia's solo reign were spent eradicating any and all traces of Nightmare's army who often tried to employ guerrilla tactics. The war came to an end in 991 years before Nightmare's return, or the year 9 in Celestia's calendar, depending on which source you use, the last of her known generals was slain in battle and thus ending the war.

There was of course, several small units of nightmare soldiers about but were eventually all caught before the end of the first century of Celestia's reign.

2: The Boreal Sea War 993 - 990

While the Oviraptors stayed neutral during the Twilight War mostly due to fighting a war with a local changeling swarm, the Oviraptors were still worshippers of Luna. The conflict with the changelings severely undermined the fighting power of their standard army at the time by the end of the conflict, but their navy, which is one of the greatest in the world then and now, were still at full strength and ready to use. During the Twilight War, the Oviraptors would sneak as much supplies as they could spare to Nightmare Moon's armies. Never some of their own, since they had to deal with the changelings.

After her defeat, many cultists were smuggled out of the country by the Oviraptors. At first, Equestria was too busy with larger forces to notice. However, near the end of the war Celestia was able to take notice of this and sent several demands, in the year 994, to the Oviraptors to give up all Nightmare cultists or there would be war. The Oviraptors did not initially take this seriously. They were an officially 'neutral' faction and hadn't been (caught) aiding Nightmare Moon's war. As well, Equestria was in a sore state of affairs given the war they were still going through cleaning up. So they did not stop.

The following year, the Equestrian navy attacked. Akin to the Oviraptor's war with the changelings, the Equestrian navy was largely still intact since there were barely any naval battles during the war and took place mostly on land. As well, the Equestrians still could bolster a large force if need be given the population size.

The naval war was a series of pushbacks from both nations. The Oviraptors had better trained and more suited ships at the time, but the Equestrians had larger quantities of ships that could replace those that were lost. While initial victors in many engagements during the first period of the war, the Oviraptors were slowly worn down. What wasn't helping was the threat of an Troodon invasion from the south. There had been some scuffles on the border of the two dinosaur nations, but nothing major. The Oviraptors couldn't afford an invasion in their sorry state. Reports were coming in that the Troodon were massing large forces on the borders.

Meanwhile, the Equestria's were slowly overtaking the Oviraptor navy as they started to adapt and make use of their numbers. Proving to be too costly, and fearing the repercussions for losing a land war, the Oviraptors sued for peace in 990. Sitting down with the Equestrian's and Troodon, it was agreed that the Oviraptors were not be forced to give up territory or pay for damages during the war. All they had to do was agree to the original terms that Celestia had laid out years before, namely to give up every single nightmare cultist they had in their possession, take down any and all organizations that were sympathetic to the efforts of Nightmare Moon, and lead Equestria to any possible cultists that were shipped off to other countries. These were quickly enacted and the war came to a close.

3: Goblin/Equestrian War 910 - 899

Having spent a few decades tracking and securing the last of the Nightmare remnants, usually on uninhabited islands or getting other nations to find them and hand them over, the last of the cultists were found in the Goblin Empire. Tensions between the two nations were high already since the goblins were known slaveholders, something Equestrians and Celestia herself detested greatly. Adding in the fact that they knowingly harbored Shadow cults due to some of them being wealthy and/or giving the goblins some benefits since goblins aren't so proficient in magic.

The goblins refused the Equestrians. Without another word, Celestia ordered an attack. Goblins weren't as proficient in long, dragged out conflicts as Equestrians were and the war mostly was this long due to the Goblin Empire being primarily composed of many scattered islands so the Equestrians had to island hop in order to defeat them. They weren't defenseless though and inflicted losses given their higher tech level.

The end of the war came with the invasion of the largest island and place of the Goblin Empire's capital city. Celestia herself led the charge, smashing through many goblin defenses after a costly beach assault. The capital city was soon surrounded and Celestia sent out a small group of ponies into the capital to create a peace treaty. The goblins, spurred on by the nightmare cultists, refused...

And sent the ponies back hanging from their now broken necks by nooses, each dressed up like Luna with a sigh that mocked Celestia.

"You never cared for your sister. Why should we care for you?"

Celestia... lost it at that moment. Her form became distorted and nothing short of nightmarish itself as she became a fiery demon god of sorts. Without much hesitation, she burned down the entire capital city in one blast, incinerating everyone inside.

Having seen the destruction and how her own forces were scared of her, Celestia, after years and years of warfare, broke. Peace was quickly set up between the Equestrians and goblins, ending their slavery and taking the few nightmare cultists that were left. Tension is still high between the two nations and which is why goblins usually supply nations not in agreement with Equestria.

Celestia became secluded from everyone, staying locked up in her study for years upon years. What should have been a celebration of the end of Nightmare, was turned into a sobering one. The Noble Council then took over in Celestia's stead.

4: Wars of Acquisition 780 - 720

The Noble Council, made up of leading nobleponies born into the station, by this time had largely become corrupt and passing laws and such that restricted many freedoms and furthered their own power. The worship of many native or foreign gods were prohibited and what appeared to be the rise of Faustian worship again, mixed in with Celestia, came to fruition.

Ultimately, to secure their power and further their influence, the Noble Council decided to take more territory for Equestria. This led to a series of small border or overseas conflicts to take lands, most of which were by pony states that had not come into Equestria's territory before.

5: Great Northern War 720 - 705

Continuing this trend, the Noble Council became aware of several rare minerals and such buried in northern territories. Most of which in Yak lands. The Noble Council quickly got the army up in arms in order to take these new lands. What followed was a long and extremely bloody war for the Equestrians. They were not prepared for such harsh climates of the north and the yaks were terrible foes to face. It did not help that many of their commanders were either inexperienced or far too overconfident in the abilities of their troops to fight in the icy terrain.

Add on to this small scale conflicts with Northern Equestrian tribes when the Noble Council tried to seize power in the tribe leaders, and Equestria was left blind and bloody in the snow. Many thousands of Equestrians lay buried in icy snow to this day from this dreadful war. As well, the yaks have the pleasure of being the only nation in Equestria's history to have defeated Equestria's army and sent it packing.

Fewer and fewer ponies were supporting this costly war since many of them felt this was just a conflict to give more bits to the nobles. Riots abounded and eventually, the Noble Council promised to end the war which they reluctantly did.

6: Equestrian Civil War 703

Tired and fed up by the Noble Council, many Equestrians still weren't satisfied with just ending the war. Many wished to try and get Celestia back on the throne and oust the Noble Council members from power. No one had the gall to do so and many were just sick of war. This sickness came to fruition when the Noble Council members announced a counterstrike against Northern Equestrian tribes for their 'treasonous aggression' towards the Council. There were also plans in the works, that were leaked, of another war against the yaks.

The ponies of Equestria were outraged, picking up arms and readying themselves for battle. Many of these were small towns, which the Nobles believed would be easy to take down. This of course caused some portions of the army to defect to the rebels, since they didn't want to fight their hometowns. Bolstered by army officials, many towns were able to fend off attacks (and showcasing the effectiveness of new muskets to Equestria). More calls to arms were held by the Noble Council, while many portions of Equestria started to rise up as well. Some Equestrians still remained loyal to the council as they were viewed by a good deal of ponies as a necessity and backed up by Faustian worship.

The fighting grew fierce over the seven months of the war. Finally, one filly was able to find Celestia and urge her to help her daddy, who was a rebel fighter. The little filly was able to break Celestia out of her stupor and she found out about the war, since the Noble Council had kept her in the dark about it. Angry over this, she teleported herself and the filly in between the two warring factions and cowed them both into submission as one would see a mother to two arguing children.

The Noble Council were then ousted from power and stripped of their wealth and prestige by Celestia. The worship of Faust was quickly crushed and finally put to an end by Celestia herself.

After this war, Celestia did her best to steer Equestria away from conflict and try and do the same for others, becoming a sort of peace keeper force. Celestia was keen on keeping the world together and for many centuries, Equestria didn't have to worry about large wars. This allowed the country to finally take a breather and relax, becoming stronger in the process.

7: War of Kratz Sovereignty 8 - 4

That is until a conflict between the Roman Empire and Equestria happened. The islands of Kratz were a contested set of islands between the two nations. Originally, thousands of years ago, they were in the possession of the Roman Empire. However, after Queen Majesty's war, they were then annexed by Equestria. Countless wars and events prevented the two empires to come to a decision. Unfortunately for many, Emperor Justinian wished to rebuild and make the Roman Empire as big as it was thousands of years ago and wanted the islands.

Using new runes that would allow their ships to traverse unseen by Equestrian magic and sight, they were able to quickly overwhelm the naval forces there and land their troops on the islands. Quickly overtaking the token Equestrian troops, the Romans were able to conquer many of the islands quite easily in the first few weeks of the war. Emperor Justinian believed the Equestrians would then concede defeat given the quick victory.

Equestria did not. A navy force unlike any other was formed and sent out to take the islands back. Many of Equestria's leading army officials as well were there in order to lead the troops. Unfortunately, the Roman ships made Equestria pay and many ships were sunk, including troop transports. This cost Equestria a number of leading army officials. After failed attempts to break the Roman blockade of the islands, the Equestrians were able to land.

Costly warfare between the two nations erupted, causing further disruption in Equestrian ranks as more officers and generals were killed due to Roman traps, assassins and such during the war. This caused many Equestrians to be quickly promoted, including Shining Armor who, by the end of the war, would be named Field Marshal. Eventually, he was able to lead counter attacks on Roman held territory. This was done with the aid of local humans of the islands who sided with the Equestrians as many felt kinship with the gods of their lands.

The Romans were eventually repelled, showing to the world that Equestria was still a nation to be reckoned with.

6101768

Wow, they really went to great lengths to find Nightmare forces.

6101786
Celestia sort of became obsessed with it, which lead to her breaking point against the goblins.

6101787

I assume the griffon war was not significant here?

6102221
which one are you referring to? Most great wars with the griffons happened before the Twilight War. Conflicts have happened, but nothing more then border conflicts or occasional scraps here or there across the globe. Nothing really to note.

6102222

Ausbrony mentioned in his story how Flare Blitz's uncle died in the "Griffon War"

6102227
Ah, that would be a technicality of griffon incursions. They happen frequently enough that Equestria sustains frequent casualties sometimes going up to 5000 or more during some years. It is not an official 'war' though some would call it that in all but name. Officially, the Griffon King is friendly with Equestria and doesn't wish for conflict. Many of his subordinates don't feel this way.

6102227
Daring Do's husband and the father of Blueblood and Cadance, was also killed in one such incursion.

6102272

Did the Planet ever experience something on the same scale as the World Wars?(not including the Kur/Alicorn galactic war)

6182479
While large scale wars were more common in the past, it matters on definition. The Deer, white tail Deer, had to fight tooth and nail over the planet against Tirek and his forces. However, if you're going by large scale, multiple faction wars. That would be the Hundred Years war about 1500 years before the present day where the Griffon Empire, finally unified, tried to conquer the world with the help of allies. They of course lost.