Second Era

Potentate Versidue-Shaie, a Tsaesci of Akavir, takes over the Cyrodiil Empire after the assassination of the last of the Reman Dynasty.
Source: The Last Year of the First Era, Mysterious Akavir.

Tjurhane Fyrre, an Ayleid sage of the University of Gwilym, published "Nature of Ayleidic Poesy". He is known as one of the Ayleids that speaks freely of his people and religion.
Source: On Wild Elves.

Tjurhane Fyrre (1E 2790-2E 227) dies.

The first Mages Guild is formed by Vanus Galerion the Mystic and Rilis XII in Firsthold, Summurset Isle, mostly as an answer to the reluctancy of the Psijics Order to deal with its evil member, Mannimarco the leader of the Necromancers.

"Like a tree from an acorn, the Mages Guild grew branches all over Summurset Isle and then to the mainland of Tamriel. There are many records of superstitious or sensibly fearful rulers forbidding the Guild in their kingdom, but their heirs or their heirs' heirs recognized the wisdom of allowing the Guild to practice. The Mages Guild was a powerful force in Tamriel, a dangerous foe if a somewhat disinterested ally. There have been only a few rare incidents of the Mages Guild actually becoming involved in local political struggles. On these occasions, the Guild's participation has been the ultimate decider in the conflict."
- from Salarth's THE ORIGIN OF THE MAGES GUILD

Source: Galerion the Mystic, Origin of Mages Guild, Imperial Charter of the Guild of Mages, Mannimarco, King of Worms.

About the time of the founding of the Mages Guild, the Isle of Artaeum vanishes from the shores of Summurset Isle. Approximately 500 years later, the Isle returns but nobody on the isle will offer any explanation for Artaeum's whereabouts during that time, or the fate of Iachesis and the original council of Artaeum.

Source: Fragment: On Artaeum.

The knightly Order of The Lamp is formed to support and protect the new formed Mages Guild.
Source: Origin of Mages Guild.

Potentate Versidue-Shaie faces lots of rebellion throughout the Empire. In the Imperial Council meeting of Bardmont, he declares catholic and universal martial law; all the princes of Tamriel have to dissolve their armies. Most of the princes resist and bloodiest wars throughout Tamriel erupt. Eventually Versidue-Shaie manages to destroy all the resisting armies.
Source: History of the Fighters Guild, First Edition

Keirgo of Anequina and Eshita of Pellitine unite their tribes forming Elsweyr.
Source: Pocket Guide to the Empire (1st Edition): Elsweyr.

Dinieras-Ves, a Tsaesci warlord forms an order of mercantile warriors-for-hire, which could be hired by nobility in lieu of a standing army. The employment would be temporary, and a percentage of the fee would go to the Potentate's government. The new order is called The Syffim, and later known as the Fighters Guild.
Source: History of the Fighters Guild, First Edition

The Fighters Guild is officially formed.
Source: History of the Fighters Guild, First Edition, Imperial Charter of the Guild of Fighters.

One of the members of Morag Tong assassinates Potentate Versidue-Shaie in his palace in what is today the Elsweyr kingdom of Senchal. Following that event, the Morag Tong is outlawed throughout the continent.
Source: Pocket Guide to the Empire (1st Edition): Cyrodiil, The Brothers of Darkness.

Savirien-Chorak, the son of Potentate Versidue-Shaie continues the Akaviri rule over Tamriel.

Some of the ex-members of the Morag Tong secretly form The Dark Brotherhood. The earliest record that contains the name of the Dark Brotherhood is in the journals of Blood Queen Arlimahera of Hegathe in 2E 412. "...with the help of the Night Mother and her Dark Brotherhood, the secret arsenal my family has employed since my grandfather's time." With this the scholars assume that the forming of the Brotherhood is as early as 2E 360.

"The important distinction between the Dark Brotherhood and the Morag Tong was that the Brotherhood was a business as much as a cult. Rulers and wealthy merchants now used the order as an assassin's guild. The Brotherhood gained the obvious benefits of a profitable enterprise, as well as the secondary benefit that no longer could rulers actively persecute them. They were needed. Even an extremely virtuous leader would be unwise to maltreat the Brotherhood."
- from Pellarne Assi's THE BROTHERS OF DARKNESS

The latest ruler of Second Empire, Potentate Savirien-Chorak, and every one of his heirs is murdered by The Dark Brotherhood/Morag Tong. This marks the end of the Second Empire.
Source: Pocket Guide to the Empire (1st Edition): Cyrodiil, The Brothers of Darkness.

Civil wars and insurrection dissolve the Tamrielic Empire.

One year after the death of Emperor Potentate Savirien-Chorak, Orsinium loses the status of Imperial territory.
Source: Pocket Guide to the Empire (1st Edition): The Wild Regions.

A naval battle is occured off the coast of Alinor in Summerset Isle between Alinor navy and Maormer. The Altmer are decimated, and left with but a single warship.
Source: Pocket Guide to the Empire (3rd Edition)

Arcturian Heresy records that Ada'Soom Dir-Kamal, a Snow Demon King of Kamal (Akavir), attempts to invade Morrowind. The Underking and Almalexia halt his efforts at Red Mountain. The question is if The Underking really is Zurin Arctus, how come he is able to work with Almalexia to thwart the Akaviri Raiders approximately 300 years before he is made in the Numidium issue? The Arcturian Heresy states The Underking is not Zurin Arctus, but the ancient King Wulfharth of Skyrim instead.

The Knahaten Flu plagues South East Tamriel destroying human tribes in Black Marsh. The reptilian Argonians are immune to the plague, leading to speculation, not entirely discredited by modern researchers, that a genocidal Argonian mage creates the plague for his people.
Source: Pocket Guide to the Empire (1st Edition): The Wild Regions, Pocket Guide to the Empire (1st Edition): Elsweyr.

Voyage of the Crimson Ship, filled with Kothringi tribesmen fleeing a deadly Knahaten Flu. The ship set out of Black Marsh on 9 First Seed. After a year of unsuccessfully trying to port at many Tamriel locations, it sets off west through the Abeccean Sea. The ship and its passengers are never to be seen again.

Akavir attacks Morrowind. Vivec teaches his people to breath water before he floods Morrowind to eradicate all Akaviri invaders.
Source: Varieties of Faith in the Empire.

Last documented case of the Knahaten Flu.

Dram the notorious Dunmer Assassin is born.

The Mages Guild of Stros M'Kai is fully chartered.

S'rathra, a Suthay-Raht Khajiit, is born. He is the future Wayrest syndicate boss of Cyrus.

In Elsweyr, the kingdom of Rimmen state their independence from Elsweyr. The population of this kingdom is mostly Akaviri refugees from Cyrodiil. When a strong Akaviri leader emerges in Cyrodiil, they join forces and try to reclaim the Empire; but the effort fails and makes Rimmen weak and vulnerable. The hapless Rimmen have once again submitted to the protection of the Elsweyr.
Source: Pocket Guide to The Empire (1st Edition): Elsweyr.

Talos (or Hjalti Early-Beard), later is known as Tiber Septim, the first Emperor of Septim Dynasty, is born. Pocket Guide to the Empire (1st Edition): Cyrodiil says he was born in Atmora, while from Elder Scrolls Calendar, he is from Alcaire, High Rock.)
Source: TES3: Morrowind Teasers - Elder Scrolls Forum.

The heirs of Camoran Dynasty of Valenwood begin to fight over the Valenwood throne. In this chaotic civil war, the Altmer of Summerset Isle invades and help one of the factions. They establish Thalmor, a provisional government on behalf of their own claimant, Camoran Anaxemes. Thus Aldmeri Dominion is formed, and consists of Summerset Isle and Valenwood.
Source: (1st Edition): Aldmeri Dominion.

Cyrus the famous Redguard mercenary is born.

General Talos destroys the allied Nord and Breton in the citadel of Sancre Tor. The Nord captives and generals eventually join General Talos’ army. They play a crucial role in General Talos' succeeding campaigns which consolidated the Colovian and Nibenean into the core of the Cyrodilic Empire, and which resulting in the crowning of General Talos as Emperor Tiber Septim.
Source: The Battle of Sancre Tor, The Legendary City of Sancre Tor.

The Emperor Cuhlecain (later is known as Emperor Zero) of Cyrodiil is assassinated by a High Rock nightblade. The assassin tries to kill General Talos as well, but the great General survives even though he loses his strong voice due the terrible wound on his neck. From this moment on, General Talos takes a Cyrodiilic name, Tiber Septim, and he takes over the throne. This marks the beginning of the Third Empire.
Source: Pocket Guide to the Empire (1st Edition): Cyrodiil.

The Empire of Tiber Septim sweeps through the kingdoms of Tamriel in a glorious bid for conquest. Septim is opposed on all sides, but never more fiercely than by Hammerfell, the home of the Redguards. The High King of Hammerfell, Thassad II, resists the Imperial invasions even as he sees other kingdoms crumble, until, at last, without warning and surprisingly devoid of court treachery, death takes its full measure. With its High King dead, Hammerfell is crippled, plunging into a bloody civil war between the Crowns, fighting for their homeland's continued sovereignty, and the Forebears, who have finally accepted the Emperor's rule. Crown Prince A'tor, son of Thassad and heir to Hammerfell, leads his forces in continual victory over the Forebears. But the latter make a pact with the Emperor, which allows Tiber Septim to bring his armies in and crush the weakened Crown forces.

Prince A'tor is forced to leave the mainland, and retreats to Stros M'Kai, the ancestral seat of the Crowns. Septim's force continues to press the weakened Crowns. At the harbor of Stros M'Kai, The Battle of Hunding Bay rages. The Imperial force faces Prince A'tor, and intends to destroy the Crowns’ resistance once and for all. The Prince and his followers fight bravely. The Imperial is nearly defeated, until the Dunmer Assassin, Dram, shoots his poisonous arrow at the Prince. Archmage Voa, the friend of the Prince and sympathizer of the Crowns' struggle tries to save the Prince, but the Dragon Nafaalilargus burns down the ship and ends the Crowns' effort to win the battle.

Fearing eventual rebellion from the headstrong Redguards, who have never suffered long under a foreign ruler, Tiber Septim establishes Imperial garrisons in every city of Hammerfell. Lord Richton, the man who beat A'tor at the Battle of Stros M'kai, is appointed Provisional Governor of that city.

Source: Pocket Guide to the Empire (1st Edition): Hammerfell, The Origin of Cyrus, Intro to Redguard.

The Battle of Hunding Bay officially marks the end of men (human) resistances. However, Tiber Septim knows that the might of his powerful army is not enough for his fledgling Empire. Therefore a pamphlet was released to the public. The pamphlet is known as The Pocket Guide to The Empire. Although the pamphlet is full of Septim's propaganda (for weakening the elves/mer), it is the first good account that has details information about each part of Tamriel.

Opposed to what the Empire thought, not all the humans of Tamriel have been subdued, in the Stros M'Kai, Cyrus the mercenary manages to move the Restless League to start a rebellion. They successfully destroy the Imperial Fleet and route the Legion. Armed with the Soulsword of Prince A’tor, Cyrus faces the Governor Amiel Richton on the top of a Dwemeri Dirigible. Although Cyrus is defeated by treachery, but the Soulsword has will of its own, and moves by itself, slaying the Governor and Dram, the Dunmeri Assassin. Eventually, The Emperor Tiber Septim is forced to sue for peace on terms favorable to Hammerfell. This is the background story of TESA: Redguard.
Source: The Story of Redguard.

Symmachus, future husband to Barenziah, is born.

In Morrowind, Dagoth Ur and his ash vampires awake refreshed and emerge from lower Red Mountain into the Heart Chamber. Dagoth Ur ritually binds himself and his brethren as heartwights in a ritual of his own devising. The first stages of the construction of the Second Numidium [conceived during the Long Sleep] are begun by heartwights and atronach constructs in a chamber near the Heart of Lorkhan. Keeping the Second Numidium project a secret from the Tribunal is a high priority.

The Tribunal arrive at Red Mountain for their annual ritual bathing in the heart's power. Dagoth Ur and his Ash Vampires ambush the Tribunal. The Tribunal is driven away, and prevented from restoring themselves with Kagrenac's tools at the Heart of Lorkhan.

Source: Dagoth Ur's Plan.

Intermittent Tribunal campaigns assault Red Mountain. The Tribunal and supporting forces seek to force access to the Heart Chamber, but are repeatedly driven back. Dagoth Ur recruits Sleepers and Dreamers through dream sendings. Cultists are recruited through dream compulsion. Weaker cultists become corprus beasts; stronger cultists advance through stages towards the powers of the Ascended Sleepers.

Barenziah, future Queen of Mournhold and later Queen of Wayrest, is born.

After Hammerfell and Morrowind, Tiber Septim turns his attention fully to Aldmeri Dominion. The joined Elven kingdoms prove too powerful, and Septim's Armada cannot defeat the Aldmeri fleet. Tiber Septim uses his latest arsenal, the Numidium (Anumidum). A Dwemeri giant construct which is rumored as a gift from Lord Vivec, during Imperial annexation of Morrowind. Numidium crushes the Aldmeri armies and in short time the Aldmeri Dominion bow down to the rule of Cyrodiil.

"Nothing is known of the circumstances of the personal meeting between Septim and Vivec, or where it took place, or the preliminaries which must have preceded the treaty. The public reason was to protect the identities of the agents involved. In the West, speculation has centered around the role of Zurin Arctus in brokering the agreement; in the East, rumors suggest that Vivec offered Numidium to aid in the conquest of the Altmer and Summerset Isle in return for significant concessions to preserve self-rule, house traditions, and religious practices in Morrowind."
- from Erramanwe's ON MORROWIND, THE IMPERIAL PROVINCE

The Dwemeri artifact, when it was given by Lord Vivec originally was not perfect. The Imperial engineers under Zurin Arctus, brings the pieces of Numidium to Halls of Colossus in Elsweyr; where it was assembled. During the assembly process, another Dragon Break occurs, although the break is not recorded in any of the Imperial records; however the Khajiit knows of this break and they suffer from it. The official Imperial records only state that The Imperial Battlemage Zurin Arctus sacrifices his heart (life force) to be infused into a gem called Mantella, and later to be implanted into the Numidium to make it fully operational. The Numidium proves very effective in bringing down the mighty Aldmeri Dominion.

The official records also state that after defeating all his enemies, Tiber Septim uses the Numidium to destroy the neutral royal families of Tamriel so that he can only enthrone persons he knew to be loyal. This brings great dispute with Zurin Arctus. The Battlemage then tries to reclaim his heart. The process devastates Numidium and Zurin Arctus. The heart they shared blows out of this reality into the netherworld known as Aetherius. Numidium's body is scattered throughout Tamriel and the Imperial Battlemage, without his life force goes into a semi-slumber in a subterranean vault. Zurin Arctus is waiting for an opportunity to reclaim his heart.

In the centuries that follow, Septim's elite soldiers (The Blades), for generation after generation, collect the pieces of the Numidium and became known as the Blades. Zurin Arctus in his undead shape becomes known as the Underking, and from time to time he sends out his forces to find the Mantella throughout Tamriel.

There are many speculations on this Numidium issue. From another account, called Arcturian Heresy, it is written that the Underking is, in fact, King Wulfharth of Skyrim, a powerful undead being from the first Era. He is tricked by Tiber Septim and Zurin Arctus, and his soul is trapped into a gem (the Mantella) to fuel the Numidium. Zurin Arctus himself is killed on the process. To prevent some political unrest, Tiber Septim states that Zurin Arctus tried to assassinate him.

"The Underking arrives and is ambushed by Imperial guards. As he takes them on, Zurin Arctus uses a soulgem on him. With his last breath, the Underking's Heart roars a hole through the Battlemage's chest. In the end, everyone is dead, the Underking has reverted back to ash, and Tiber Septim strolls in to take the soulgem. When the Elder Council arrives, he tells them about the second attempt on his life, this time by his trusted battle mage, Zurin Arctus, who was attempting a coup. He has the dead guards celebrated as heroes, even the one who was blasted to ash... He warns Cyrodiil about the dangers within, but says he has a solution to the dangers without. The Mantella."
- from ARCTURIAN HERESY

Source: The Story of Daggerfall: The Numidium, Skeleton Man's interview, Arcturian Heresy, A Brief History of the Empire, Daggerfall Intro.