I decided to write this as a guide to the 4th era Empire mostly because it seems people seem to have different ideas as to what happened in that time frame Mostly this is just to discuss the politics and history of the era so anyone can join in if they want lol. Also I apologize for the wall of text.

The Oblivion Crisis and its' aftermath

We all know how the story of Oblivion went as well as how the crisis ended with the death of Emperor Martin and the end of his dynasty. Many people seem to think that the Empire abandoned its' provinces in order to protect Cyrodiil. I think this is wrong. During the quest Allies for Bruma, Ocato states that troops can't be spared for the defense of Bruma as they are tied down in the proviences. Obviously that means the legions didn't abandon the provinces. The belief that the imperials abandoned eveyone, I believe, comes from the scale of the Crisis. The legions probably either moved around playing wack-a-mole with the oblivion gates or, more likely, stayed to protect the major cities. This would mean large swaths of the countryside wouldn't see legion troops and could halp explain why people, such as the Dunmer of Morrowind and Solthseim, believed the Empire to have abandoned them. Also if the attacks we as severe as the one described in The Rising Threat I could see all troops involved, imperial and provincial, losing a good chunk of their numbers. This seeming absence of troops and self defense by local forces, such as the Argonian offensives in Black Marsh, Redoran's army in Morrowind, and the Altmer in Summerset, meant a loss of faith in the central government.

With the death of Emperor Martin the Empire entered a period of turmoil The central government does not seem have been in turmoil that long as they moved quickly to apoint Ocato as Potentate. The problem was with diminished influence and weakened troop strength some of the provinces believed they could go it alone as they believed they had in the Crisis. It seems that the only province to actually revolt at this time though were the Argonians of Black Marsh. According to the Rising Threat, the Empire was making progress to restoring Tamriel to the way it was before the Oblivion Crisis. Likewise by the Red Year it doesn't seem like any other provinces had risen up in revolt and there were still imperial garrisons in Black Marsh.

The Red Year of 4E 6 seemed to change everything. Morrowind would be obviously damaged but I have no doubt the parts of Skyrim and Cyrodiil were also probably affected by the eruption. It also seemed to cut of the roads to the garrisons in Black Marsh. The ensuing Argonian invasion of Morrowind probably saw the fall of the remaining imperial garrisons in Black Marsh as well as damaging the half of Morrowind probably least affected by the eruption of Red mountain. Ocato's work of the preceding 6 years is most likely undone and I have no doubt that the chaos caused by the eruption and invasion would not be corrected by the time Ocato is assassinated in 4E 10. The death of Ocato fragments the Empire. The Empire probably stops any attacks on Black Marsh at this time as well as most help to Morrowind. The Thalmor also take this time to seize Summerset control of Summerset though they don't seem to have actually left the Empire until 4E 22. The rest of the Empire probably saw warlordism, internal fights, and the damage that this causes. When Titus Mede takes over in 4E 17 it probably wasn't total control for some time. The Thalmor seem to take advantage of this time and the weakness of the Empire to remove Summerset from the Empire and to seize Valenwood in 4E 29.

I will probably deal with the Great War next but we shall see how things go. I'd love to hear people's opinions.