The story of the Old World, or as it has been called on occasion 'Old Equestria' begins with greed. Equestria had been thrown into a time of technological advances, weapons and vehicles and thousands of machines were being built by massive machines powered by unicorn magic, Pegasii had begun construction of massive airships, and Earth ponies began to use machines to do many of the tasks previously done by hoof. This golden age of advancement was, however, short lived. With the creation of these machines valuable resources were being used up trying to power them, Gems that Earth ponies used to power their machines were almost non-existent since they were all mined out of the earth, and various chemicals that the Pegasii used to power their machines were nearly drained as well. However unicorn devices that ran off of talismans and raw magic still remained active much of Equestria began to fade from a time of advancement and growth to a time of nation-wide poverty. With the dramatic difference between the quality of living for unicorns and Pegasii and Earth ponies riots began to rise as the rage driven crowds of Pegasii and Earth ponies savagely attacked any Unicorns they could find and breaking into factories that ran on Unicorn magic to destroy the machinery.
With Equestria slowly fading the two Princesses turned their gazes to the eastern sea, pleading with their allies in Saddle Arabia to lend aid to their dieing empire, though their eastern allies, with their country facing the same issues, could not spare the resources needed to fix the problem they suggested another way to aid both empires, invasion.
With the preparation for war, the two sisters feared the outcome if they were to fail in this attempt to save their land, and thus created a contingency plan, building hundreds of bunkers throughout Equestria, placing the six in charge of overseeing the preparation of these bunkers. Though these bunkers were mainly to keep a select few safe from the war outside these bunkers also were to house various social experiments, using experimental machinery and chemicals and many other various technologies. Many others were placed in charge of several other operations but those details are actually as irrelevant as many believe.
With Equestria desperate for resources the two sisters gathered their armies to invade the land of the Zebras, with the forces of Saddle Arabia preparing to do the same. The two armies entered the unfamiliar land in hopes to conquer it and divide the precious stones beneath the earth and other plentiful resources between themselves. Little did they know that another army of much greater power had plans to do the same.
To this day little is known of why exactly the Griffins had invaded Equestria, though many believe it was an obvious attempt to claim their land, the details were mostly lost with time. However no matter why it happened, the only thing that i suppose matters is that it did. Griffins swarmed from the northern lands, carried in flying vessels that dwarfed some of the largest Pegasus carriers of the time. With over half of Equestria's forces in the land south across the sea, the Griffin invasion became a devastating massacre.
With hundreds of deaths occurring with each passing minute the two sisters called upon the six to aid them in Canterlot. Along with the six the Prince of the crystal empire, Shining armor, with Princess Cadence dead and his empire in flames he made his way to Canterlot to make a final stand with what few of his forces were still alive. At the gates of the Castle in Canterlot the six and Shining armor made a desperate attempt to fight off the hundreds of Griffins that stood before them and protect the two sisters.
As the fighting in Canterlot continued word was received that across the sea forces were retreating back to Equestria, and that the Zebra's had managed to fight off the invasion and all communication had been lost with Saddle Arabia. Along with the waves of Equestria's forces that arrived on the eastern shoreline twice their number in Zebra's had followed. By the fifth day of fighting at Canterlot The young Earth pony mare Applejack had been killled in the fighting, as well as her older brother, who died in a desperate attempt to retrieve her body from the front lines, as well as the yellow Pegasus, Fluttershy, who was killed when a Griffin squad breached through the windows and into the Castle where the wounded were being kept. With two of the Six dead and all of Equestria burning the line could not be held and after Shining armor had made a last attempt to protect the sisters, shorty after the the thrown room was breached. Upon the arrival of the remaining of the six the bodies of Shining armor and Celestia were found, the body of the younger sister was not found, nor any sign of Luna's presence was found in the thrown room, as well as the Griffins who had breached the room.
After inspection of the thrown room it was discovered that Celestia had attempted to initiate a contingency plan before she was killed, this contingency plan was hundreds of projectiles carrying megaspells within them, with their targets spanning not just Equestria but Saddle Arabia, the Land of the Zebra's, and the Homeland of the Griffins beyond the Frozen North, as well as many other various places throughout the known world. With the Griffins approaching the thrown room, two of the six dead as well as Celestia and Luna missing and Equestria in ashes, the remaining four decided to do what their leader could not. the four had put an end to the world's pain and had initiated the contingency plan, and launched the megaspells. From the time The Griffins had reached Canterlot to the time the megaspells were launched was seven days to the hour, and in the final, violent moments of the old world's existence, and so the burning world did not die with a terrible roar, but with a whimper. Ever since the ruins of Equestria had been referred to as the Kingdom of Ashes.
But..that's all irrelevant now..