The Colovian Estates were a separate nation of Cyrodiil. It existed at the time of the Alessian Order, largely because the subjects of Colovia did not wish to believe in the singular monotheistic religion put forth by the Alessian Doctrines. Instead, they wished to continue in their belief of the Eight Divines. They are known as Western Cyrodiilics, as they come from the western section of Cyrodiil.
Bendu Olo was the Colovian king of Anvil. He led the Colovians in the All Flags Navy to victory over the slugfolk of Thras, to stop the Thrassian Plague of 1E 2200. The Colovian Estates began to overshadow the richer, more populous east then, which eventually led to the War of Righteousness that ended the Alessian Order. Control of the Nibenay Valley then returned to a mercantile-based rule by magicians, whom the Colovians despised. They parted ways once more until the time of Reman I.
Four hundred years after the War of Righteousness, Reman Cyrodiil I, another Colovian, rallied his armies with that of the Nibenay Valley, to fight off the Akaviri Invasion of 1E 2703. The Cyrodilic forces engaged the Akaviri in every region of the north, forcing their surrender at last in the Pale Pass of Skyrim.
Titus Mede I was the first Emperor of the Mede Dynasty. He was the Emperor during the events of The Infernal City. He came to power after the Oblivion Crisis and Martin Septim's sacrifice, which ended the Septim Dynasty. Mede took the Imperial City by force with only 1,000 men, usurping the current emperor at that time, Thules the Gibbering, and becoming Emperor of Tamriel.