Natives of the civilized cosmopolitan province of Cyrodiil, they have proved to be shrewd diplomats and traders. They are skilled with heavy armor and in the social skills and tend to favor the warrior classes.
Natives of the civilized, cosmopolitan province of Cyrodiil, the Imperials are well-educated and well-spoken. Imperials are also known for the discipline and training of their citizen armies. With this they were able to fight off the Redguard and control most of Tamriel. Though physically less imposing than the other races, the Imperials have proved to be shrewd diplomats and traders, and these traits, along with their remarkable skill and training as light infantry, have enabled them to subdue all the other nations and races, and to have erected the monument to peace and prosperity that comprises the Glorious Empire. Imperials have a grudge on the Khajiit. The Imperials control most ports in Tamriel and are similar in appearance to Bretons despite their darker skin color.
The Imperials forcibly took control of Tamriel under the leadership of Tiber Septim, all provinces of Tamriel were brought under Imperial rule by force except for Morrowind, they were brought in by treaty, so they are allowed most of their privileges they had before hand. More detail can be found here.