NOTE: This is of course 100% unofficial; it's my subjective interpretation of the Timeline pages and events as I understood them.

The 400-Year Darkness
  • 424ABY: The height of recorded civilization. All destroyed worlds have been rebuilt through technology and biotechnology.
  • 425ABY: The Gulag plague spreads rapidly, killing trillions and forcing planets into paranoia and isolation. The 400-Year Darkness begins. This event affected people on every major world.
  • ~750ABY: The Gulag plague largely dies off. The 400-Year Darkness will continue for nearly another century.
  • 835ABY: Rise of the first true interstellar governments in centuries. Ben Watts and Teferi Artemis unite the scattered Jedi and found the modern Jedi Order at a temple on Coruscant. The malevolent AI named Omni unleashes buried forces of droids and nanotechnology on many worlds - the so-called Clockwork Rebellion. Omni's nanotech turns millions to his cause. This event affected people on every major world.
  • 836ABY: Undead incursions on several worlds, including Dagobah: the Dark Harvest crisis. Fleets from all major governments clash at Polis Massa.
  • 837ABY: The First Akala Crisis. Many beings experience visions of obscure prehistoric events, undergo possession by the ancient being Akala, and battle Akala's servants on a Kwa artificial planet called Ash. Akala leaves the galaxy.
  • 838ABY: The One Sith emerge from centuries of hiding and sack Coruscant.
  • 844ABY: The Netherworld Crisis or Second Akala Crisis. Across the galaxy, billions vanish into the Netherworld. Many manage to escape through various portals. Planets from the Yuuzhan Vong galaxy appear; one merges cataclysmically with Corellia. This event affected people on every major world.
  • 845ABY: Several major governments (primarily the Lords of the Fringe and the Omega Protectorate) collapse in the aftermath of the Netherworld Crisis.
  • 846ABY: The One Sith finish their conquest of the Galactic Core and extend their reach farther.
  • 847ABY: The Galactic Alliance and their friends break the One Sith hold over the Core. The Underground sets up shop in the Kathol Outback (later the Outer Rim Coalition, then Outer Planets Alliance).
  • 848ABY: Weakened by ten years of losses against the One Sith, the Republic is annihilated by the Mandalorians.
  • 849ABY: Rogue Sith create Omega - the first true superweapon since the start of the 400-Year Darkness. Many governments and individuals work together to destroy it. The First Order and the Galactic Alliance go to war.
  • 850ABY: The Sith rise again as the Sith Empire under Darth Carnifex.
  • 851ABY: The First Order has achieved eighteen months of sustained success against the Galactic Alliance.
  • 852-856ABY: The Great Galactic War sees the end of many governments. This event affected people on every major world. A long-term Sith plot and the First Order war machine destroy the Galactic Alliance, whose survivors flee to the Outer Rim and the Silver Jedi.
  • 856-858ABY: The Ssi-Ruuk destroy the First Order. The Sharukan Empire menaces the Outer Rim. For the most part, though, the galaxy experiences its first recent stretch of relative peace as the great powers focus on expansion rather than direct competition.
  • 860ABY: Present day. The Sith Empire, the Silver Jedi, the CIS, and the Outer Planets Alliance are the galaxy's most powerful, longstanding governments. A surge of local independence movements creates a huge diversity of smaller interstellar governments. A long-awaited open war breaks out between the Sith Empire and the Silver Jedi.