Timeline

985 SSC – Twilight Sparkle is born.

1000 SSC – Nightmare Moon returns to Equestria and is purified by the Elements of Harmony.

1007 SSC – Velitza Disaster occurs.

1017 SSC – An attempt at diplomatic contact with the Confederacy results in the Geos Incident. Princess Celestia is dead and Princess Luna is missing and presumed dead. The lack of a designated heir to the throne of the Kingdom of Equestria creates a crisis. A large faction of mercantilists settle on reforming Equestria into a democracy over which they have immense and malign influence, resulting in the formation of the Equestrian Republic.

1018 SSC – This year marks the formation of the Torchbearers secret society by Twilight Sparkle, to avenge Princess Celestia and restore monarchic rule by alicorns.

1025 SSC – The Avalon Raid secures evidence of Confederate Military Intelligence’s wrongdoings. That same year, Twilight Sparkle rises to power after winning the vote using extremist tactics and intimidation.

1027 SSC – The Twilight Conclave is formed to investigate advanced applications of science, technology, and magic for military and industrial purposes.

1029 SSC – Fearing the rising militarism of their neighbor under Twilight Sparkle’s rule, the Crystal Empire declares war on the Equestrian Republic. In response, the Equestrian Republic invades and rapidly annexes the Crystal Empire. With the seizure of the Crystal Empire’s lands, the Equestrian Republic changes their form of government to an Imperial one, and Twilight Sparkle declares herself the first Empress. Princess Cadance and Prince Shining Armor are sentenced to exile.

1031 SSC – Dissatisfied with Twilight Sparkle’s leadership and her tyrannical use of power, the Torchbearers become unruly. Twilight Sparkle has them disbanded. Many of their former members are arrested by the Conclave. Some are recruited, swayed by the Empress’s vision. Some resist, and are killed.

1034 SSC – Outbreak of the Zeppelin Wars between the Equestrian Empire, the Griffon Kingdom, Farasi, Yakyakistan, Abyssinia, and the Storm King. Decades of brutal and increasingly industrialized trench warfare follow, at the cost of hundreds of thousands of lives.

1042 SSC – The first Charger Corps is formed. These are elite heavy infantry units consisting of ponies in thick, bombproof armor who are armed with spar torpedoes. Their role is to literally charge on hoof at enemy tanks and destroy them by hitting them directly with shaped charges.

1078 SSC – The Equestrian Empire conquers the entirety of Equus and renames the planet Equestria. The Empire undergoes massive growth and advancement in the fields of heavy industry, transportation, medicine, and more.

1109 SSC – The Everfree forest is cut down and leveled and a spaceport is built, its remoteness chosen particularly for containing any possible accidents with early spacecraft.

1131 SSC – The area between Everfree forest, Ponyville, and Canterlot is increasingly urbanized. The entire region is designated as the Everfree Metropolitan Area. Space development in the vicinity of Equestria is proceeding rapidly.

1176 SSC – War is declared on the Cleomanni Confederacy by the Equestrian Empire. First planetary skirmishes occur in the same year. Most end in losses for Equestria due to inferior technology. The few victorious battles yield salvage which is promptly reverse-engineered.

1217 SSC – Canterlot and Ponyville merge to become mere outlying districts of what is now Everfree City, a metropolis that spans the entire region. Ground is broken for a new palace complex as Equestria moves its capital there.

1305 SSC – The first Charger, the Sword Bayonet H4, is unveiled. The Charger Corps are reorganized as mechanized walker units.

1921 SSC – After centuries of hard-fought warfare and colonization of frontier worlds, the Equestrian Empire reaches its zenith, possessed of 94 planets and a population of over 120 billion.

2154 SSC – The Empire suffers loss after loss as their colony worlds are destroyed one by one by the Confederacy’s numerically superior fleets. Empress Twilight Sparkle organizes defensive actions on many worlds directly in the path of the Confederate offensive, many times even participating directly in combat. This proves fruitless.

2167 SSC – A ceasefire between the Equestrian Empire and the Cleomanni Confederacy is declared.

2174 SSC – Sonnem Bertag’s Carpentaria expedition is destroyed by unknown forces.

2176 SSC – Salzaon Granthis is elected president of the Cleomanni Confederacy on the 1000-year anniversary of the conflict. War with the Equestrian Empire resumes.

2178 SSC – Two years of brutal conflict have led the Confederacy straight to the Empire’s doorstep. Everfree City is bombarded by Confederate fleets and invaded by small strike teams. Empress Sparkle is missing and presumed captured. The siege of Everfree City and the failure of the Empire’s Continuity of Government plans lead to mass starvation among the survivors. There are reports of rioting, gang warfare, and cannibalism. The Equestrian Empire has fallen.

2181 SSC – Major action on Equestria between Confederate forces and the Equestrian Liberation Front. The conflict is renewed over the matter of a nuclear warhead being detonated in the midst of a Confederate Army formation in the Crystal Mountains. There are multiple reports of active Chargers in combat with Confederate forces.