Cyrodiilic Rebellion

The Cyrodiilic Rebellion was a Second Era revolt against High King Titus I of Cyrodiil. Sensing a weakening of power in the kingdom, a number of vassals organized a confederacy to demand independence from King Titus. While the king's armies were away fighting a war in Skyrim, the rebels struck and began to seize territory in the name of the rebellion. Disorganized and disadvantaged, the king attempted to win two wars at once, which did not work in his favor.

Origins
High King Titus I, a third generation Vallerion, had recently ascended to the throne after the abdication of his father, the Mad King Caius II. Titus was viewed as weak by many, an image he attempted to get rid of by invading Skyrim. Starting with The Rift, Titus' armies marched north into the snowy marches of the neighboring kingdom.

Skyrim was remarkably cold, however, and the king's armies were not prepared to fight a war in such conditions. Thousands died from the frigid conditions, and thousands more died in the actual fighting. Titus regretted the decision to send so many of his men to die, but was at his wits end of how to earn his vassals' respect.

Meanwhile, a coalition of Counts and Countesses were meeting in secrecy to win their independence. The same vassals that viewed Titus as weak believed they could defeat him and make themselves independent rulers. Their initial goal was to overthrow the king completely, but they recognized that even if they could defeat the king's armies in battle, his garrisons in the Imperial City would be an impossible nut to crack. From there, they settled for independence.

A Futile Effort
While the king was away, the faction decided to strike. An army on par with Titus' was raised, demanding independence. By the time Titus received the news while on campaign, the rebellion had already not only started but achieved a great deal of progress. The king was faced with a decision to either abandon his war in Skyrim or to finish it and then march south. Confident that he could not only crush The Rift but the rebellion as well, he decided to finish what he started in the north.

This proved to be a massive mistake, as by the time he defeated The Rift, the rebellion had assembled its host into a single, massive army that outnumbered the king's by several thousand men. Growing desperate, Titus hired the Fighters' Guild to assist him. After moving his armies down south to rendevous with the guild, King Titus attempted a single, massive assault on the rebel armies in County Cheydinhal. The Battle of Cheydinhal was absolutely massive, but ended with a total defeat of the king and his loyalists. With only a few thousand survivors, King Titus was forced to admit defeat and submit to his former vassals' demands.

Aftermath
In total, eight new independent counties were born as a result of the rebellion's success. King Titus faced a nearly complete destruction of his armies, leaving him in an incredibly weakened state. Despite losing much land to the rebels, King Titus still retained control of the majority of Cyrodiil.