Following the flight of the Phoenix, created by Zephram Cochrane and Lily Sloan, a Vulcan science vessel lands on Earth at Cochrane's camp in Bozeman, Montana. Cochrane leads an attack force against the ship and claims it's superior technology. These technology thieves would eventually become what we know as the Terran Empire, who would go on to enslave billions. (In a Mirror, Darkly Part 1)

Commander Jonathan Archer of the I.S.S. Enterprise (Equivalent to the Enterprise NX-01) leads a mutiny against Captain Maximilian Forrest. Archer then takes the I.S.S. Enterprise into Tholian Space, where a highly advanced starship has been discovered.  Commander T'Pol conspires against "Captain" Archer and returns command of the I.S.S. Enterprise back to Captain Forrest., Archer locked the helm system into a course for the Tholian Station where the starship is being contained. Upon their arrival, crew members of the I.S.S. Enteprise were able to steal the ship, the U.S.S. Defiant that went missing from the Star Trek Universe we know, but not before the I.S.S. Enterprise was destroyed, but not with all hands, escape pods were released and the crew was beamed onto the Defiant, Captain Forrest sacrificed himself to save the crew. (In a Mirror, Darkly Part 1)

Archer takes command of the Defiant and intended on conquering the Terran Empire for himself, by threatening (or destroying, if they don't give in) Star Fleet Command and the Emperor. But his consort, Hoshi Soto, had other plans and poisoned Archer and took the Defiant and the Empire for herself. (On a Mirror, Darkly Part 2)

Hoshi Soto, the new Empress of the Terran Empire, with the help of the Defiant and with the support of her newest consort General Shran of the Andorian Imperial guard is able to cement her power. But Shran betrays her, in order to keep herself Empress, she forms an alliance with the Vulcans, granting them full citizenship and creates an everlasting loyalty of the Vulcans to the Empire. T'Pol is made regent of Vulcan aswell. (Star Trek Mirror Universe Series, Book 1: Glass Empires, Part 1 "Age of the Empress") Empress Soto creates a clone of Jonathan Archer to serve at her side after the betrayal of Shran. But the clone rejects Soto's influence and joins the Rebellion against the Empire. (Age of the Empress from Glass Empires, "Nobunaga")

Commander Charles Tucker III, is instructed by Empress Soto to re-engineer the Defiant, which she calls Nubunaga. ("Nobunaga")

Commodore April commander of the I.S.S. Constellation takes over a mission to destroy a new weapon that was in development by the Klingon Empire, after the failure of Captain Thorpe of the I.S.S. Indomitable. ("III Winds")

Lieutenant Commander James T. Kirk, after having manipulated events on the I.S.S. Faragut so that the entire command crew would we killed by an energy creature (the counterpart of what was described in the TOS Episode: Metamorphosis). He sets his eye on the command of the I.S.S. Enterprise, he befriends the ship's second officer, Lieutenant Spock . He then travels to the Tantalus Mining Colony for a psychological evaluation following the Faragut tragedy, Kirk and his consort, Marlena Moreau, discover a device that can monitor and eliminate anyone. Kirk uses the "Tantalus" device (described in "Mirror, Mirror" as the "Tantalus Field"),  to eliminate Captain Pike and his First Officer ("Number One" same as in "The Cage"), thus taking command of the I.S.S. Enterprise. ("The Greater Good, Mirror, Mirror)

After the Halkans decide to not surrender to the Empire, Kirk and the landing party beam back to the Enterprise, but they exchange places with their counterparts in the parallel universe where the Defiant came from. The Parallel Kirk convinces Spock that the Terran Empire is illogical and must be destroyed, and that Spock should hasten the collapse for the benefit of everyone under the jurisdiction of the Empire. He also tells Spock of the Tantalus device. ("Mirror, Mirror")

Upon his return, Captain Kirk makes a full report about the other Universe. Starfleet, like any bureaucracy, covers it up. They instruct all transporters to be altered so that this could never happen again. Kirk orders the Halkans destroyed. After their destruction Spock kills Kirk and Kirk's "faction" and takes Command of the Enterprise. He also convinces his father, Ambassador Sarek, that his plan is the right one for the Empire. (The Sorrows of the Empire, from Glass Empires, "Crossover")

Spock begins cementing his power by the use of the Tantalus device. He does this both by eliminating his rivals on board the Enterprise and achieving amazing victories with minimal bloodshed. Also he was able to convince Elas and Troyius to grant dilithium mining rights, not for the Empire but for himself.

In the Parallel Universe (our universe), the U.S.S. Defiant travels through the unstable region of space near Tholian territory. It disapeers into an intersphasic rift and it ends up in the Mirror Universe in the year 2155. ("The Tholian Web", "In a Mirror, Darkly")

Spock has spent the last decade creating many alliances for the Empire and promoting an agenda of peace, with using negotiation techniques instead of conquest, this makes him seem weak to his commanders. With the Tantalus device he saves himself from assassination attempts and eventually kills Grand Admiral Matt Decker. He declares himself Grand Admiral and returns to Earth, having his associate, Ensign Savik, use the Tantalus device to kill Empress Soto III and her guard. Spock then declares himself Emperor. (The Sorrows of the Empire, from Glass Empires)

Emperor Spock created groundbreaking reforms that bring the Empire closer to Republic every day. He instructs Doctors Carol and David Markus to form "Memory Omega" which will be the storehouse of all of the knowledge collected by the Empire, to insure that after the Empire's Fall, all of that knowledge can be used to create a new Republic by the the former citizens of the Empire

-Spock's master plan was that he knew that the Empire would fall, so in order to secure future prosperity for the Galaxy, a republic needs to be formed. But since the empire is to conquered (by the Klingon/Cardassian Alliance) he knows that any republic he forms will not last long, because with a new "Weak" republic, the Empire would show weakness and it will be conquered, so in order to make sure that a new Republic will be created in the future he sets in motion his plan. His plan to ensure a new republic is that he  gives the people a taste of personal freedom so when that freedom is taken from them (by the Alliance), they will go to great lengths in order to regain their freedom, and create a new Republic. (Almost like the American Revolution) (The Sorrows of the Empire, from Glass Empires)

Spock begins laying his groundwork for the long term elements to his plan, he recruits many Vulcans to serve at his side and also reducing the Empire's defenses. (The Sorrows of the Empire, from Glass Empires)

Following the destruction of the Klingon Moon Praxis, a summit is held on the planet Khitomer near the Romulan Border, Regent Gorkon of the Klingon Empire offers an alliance to the Terran Empire, Spock refuses. He also refuses a similar offer from the Romulan Star Empire. Soon after he declares that the Terran Empire is to be dismantled and a new republic, the Terran Republic is to replace it. He remains as Consul. (Sorrows of Empire, from Glass Empires, The Mirror-Scaled Serpent, from Obsidian Alliances)

An alliance is struck between the Klingon Empire and the Cardassian Union. The Interstellar Alliance quickly conquers the Terran Republic. Consul Spock and Moreu are assassinated by Regent Gorkon and Legate Renar, leaving all of the former citizens of the republic as slaves. Several Vulcans now serve in the Alliance as sleeper agents, including Savik and Tuvok, with the goal of achieving Spock's dream of peace. The key piece to the plan is the Memory Omega planetoid where key personnel, information and supplies have been placed without the Alliances' knowledge. (The Sorrows of Empire from Glass Empires, The Mirror-Scaled Serpent from Obsidian Alliances)

The Laakul, a cargo ship under the command of Guinan with Ben Zoma as her first mate, attempts to convince the Daa'Vit, a warrior race who have been on good terms with the Klingons, as allies in a rebellion against the Alliance. (The Traitor)

A rebellion is put down on Xenex, a world under the control of the Romulans. The rebellion was lead by D'ndai of  the Calhoun, the son of the chief Gr'zy. After the rebellion Gr'zy's younger son M'k'n'z'y, is taken by Praetor Hiren as a hostage to ensure Gr'zy's obedience to the Empire. (Cutting Ties from Obsidian Alliance)

Gr'zy leads another rebellion against the Romulan Empire. Hirem orders M'k'n'z'y who he nicknamed "Muck", to kill his father. He could not do it, but Gr'zy commits suicide by jumping on Muck's knife. Hiren sends Muck to the Reman Mines. (Cutting Ties from Obsidian Alliance)

ON the mines at Korvat, Keiko Ishikawa gets into a fight with a Terran slave, who wants to sleep with her. But then she sleeps with a Cardassian guard, as she prefers to sleep with people that will improve her status amongst the slaves. ("A Terrible Beauty")

Keiko informs Gul Zarale of a slave rebellion on Korvat, which is under his command. This leads Keiko to become one of Zarale's "comfort" Women. ("A Terrible Beauty")

Keiko becomes respected enough with Zarale to become an overseer of the slaves. One of the slaves is Tiron. ("A Terrible Beauty")

A Starfleet runabout from the parallel universe (the normal universe) arrives in the Bajoran system and is taken to Terok Nor. It is piloted by Kira Nerys, the counterpart of the Intendant of Bajor, and Dr. Bashir, the counterpart of a Terran slave. By talking about their universe to the slaves, Benjamin Sisko and Miles "Smiley" O'Brian, the two slaves realize that a rebellion against the alliance is possible. Sisko helps Kiran and Bashir to return to the parallel universe, and he initiates the Terran Rebellion.

En route to Terok Not to convince his ex-wife Jennifer to stop working for the Alliance, Sisko's Ship is destryed. O'Brian transports to the parallel universe to bring back Sisko to complete the mission. While he was there, Smiley also downloads a ton of information, including the specifications for the Defiant, Siskp reluctantly performs the mission and Jennifer joins the rebellion. ("Through the Looking Glass", "Shattered Mirror") JEan-luc Picard an archeologist in the service of Gul Madred, learns that his lover on and off lover is a member of the Alliance. His shuttle the Stargazer was broken into by a band of Klingons who ransack the place and drink Picard's treasured last surviving bottle of Wine from Picard's Family Vineyard. After this he agrees to be taken by Vash to meet a scientist, Dr. Noonien Soong, who believes there is a threat from a species known as the Borg. Together Soong and Picard find the Borg, who cut a path through Alliance territory.  Picard is able to stop them with the aid of a piece of ancient Iconian Technology, but not before Soong and Vash are assimiliated and Madred is killed. ("The Worst of Both Worlds, Obsidian Alliances")

Most of the Above is from our few glimpses into the Mirror Universe, through the 5 episodes. But it is supplemented by the series, Star Trek: The Mirror Universe Series, a compilation of different short novels combined, each on a different time period (each series), the two books are Glass Empires and Obsidian Alliances, also it is supplemented by many different books such as the books "Three" or "Crossover". This article is an ever expanding article and will be updated frequently. Most of this timeline is mere speculation of possible outcomes that seem to fit the bill.