The national flag of the Empire of Tamriel has changed multiple times through the many years, dynasties, dis-establishments and re-establishments of the Empire.

While many regional banners and flags existed in Tamriel previously, the first official national flag of the Empire enacted by the Elder Council was done so during the Third Empire, shortly after its establishment by the Emperor Tiber Septim. This version was described according to the contemporary Bretonnic heraldic standards in the enacted law as:

Elder Council Decree No. 26 ("The First Flag and Heraldry Act") §2, c. 1 sub-c. 1:

A field Red; five twelfths field's width charge of Akatosh Black upon fly and hoist. Width of three feet; length of five feet.

In 3E 40, the flag was changed, making the charge of Akatosh gold instead of black. This change was made following certain reforms in the Imperial Legion and in the greater government. This flag was no longer used in military locations or as an ensign, and variant designs were instead produced for these roles. The flag remained the same through the fall of the Septim Dynasty.

Following the Oblivion Crisis and the end of the Septim bloodline, the flag was changed again, removing the small diamond portion of the charge of Akatosh, which represented the Septim blood. This change was reflected across all new instances of the Akatosh design.

Then, in 4E 17, with the institution of the Mede Dynasty, the flag was again modified, making the charge of Akatosh black, and the field's color of red was darkened slightly.

This flag remained in use until 4E 171, when a gold border was added around the edges in an effort to counteract the negative social effects of the Great War. A similar design was also put into place on military banners and pennants, mainly differing in the aspect ratio. This flag was used through the Second Great War in the 4E 240s, until after the end of the Mede Dynasty.

The flag was changed again in 4E 422 by the Emperor Cassyndrus Amatore after he instituted the new Amatore Dynasty as the ruling family in the Third Empire. Along with his radical reforms in the government, backed by his unprecedented favor among the people, he introduced a flag with a new angular design and added the color white.

It was described in the enacted law as:

Elder Council Decree No. 3-0 ("The Cumulative Amatore Dynasty Transition Act") §15, c. 2 sub-c. 1:

A field Red; one third field's width fess White upon fly; one third field's length chevron Gold upon fly; five twelfths field's width charge of Akatosh Black upon fly and hoist of chevron. Width of three feet; length of six feet.

This flag remained in use until 4E 603, at the declaration of the War on the World by the Aldmeri Dominion. At this time, the flag's design remained the same, but the chevron was changed to red, field to gold and fess to black. This version remained in use until the fall of the Third Empire, and the end of the Fourth Era, in 4E 889.

The change in color represented the rapid betrayal and face-heel turn of the Aldmeri Dominion against everything else in existence. The Dominion's War on the World progressed and escalated until, finally, the Numidium was activated, splitting the path of the Dream into two primary directions: an unchanged version, in which the events of C0DA took place, and a reset version, known as the Contingency fork, which removed the Numidium and all sentiment of Dominion supremacy and altered several other parts of the Dream. In the unchanged version, the moniker of the Empire of Tamriel did not persist, but in the Contingency fork, the Empire was founded anew by the Empress Syllisia Calvieri in 5E 1.

From this point on this article will be dealing with events in the Contingency fork alone.

The flag was again changed by Syllisia's regime, however the design stayed mostly the same. It was described in the enacted law as:

Elder Council Act 0-000 ("The Establishment of the Fourth Great Empire of Tamriel Act") §11, c. 4 sub-c. 1:

A field Red; one third field's width fess Black upon fly; two fifths field's length chevron Gold upon fly; five twelfths field's width charge of Akatosh Black upon fly and hoist of chevron. Width of three feet; length of five feet.

In addition to this new Empire-wide design, individual provincial flags were designed at this point.

This flag was used until the end of the Calvieri Dynasty in 5E 225. It was subtly changed at this point by the newly instated Feyglia Dynasty, widening the fess to one half field's width from one third field's width.

The flag was again changed in 5E 401 following the upstart Nu-Alessian Rebellion's violent demonstrations at the Empire's quadricentennial anniversary celebration. The field was made black and the fess was made red to represent the grief of the nation. The rebellion was unsuccessfully quelled, and thus the Empire fell 28 years later, in 5E 429. The flag was retired along with the Fourth Empire.

After the fall of the Fourth Empire, the various regions of the former Cyrod went their separate ways, forming many small fiefdoms, duchies, kingdoms, et cetera. Despite their being entirely dwarfed by the bordering nations of the Serene Republic of the Niben and the People's Republic of Colovia, these two republics were ransacked and eventually brought down by the smaller Cyrod states. The fall of the Serene Republic of the Niben began the Barbarian Interregnum, which lasted from 5E 504 to 5E 581.

The Interregnum was ended by the founding of the Fifth Empire in 5E 581, which revived the use of the second flag design from the Fourth Empire.

The flag's design was changed again in 5E 822 with the rule of the Kesztell Dynasty. It was the first state flag since 4E 422 to not use a chevron in its design. It was described in the enacted law as:

Elder Council Act 1-059 ("The Second Flag Act") §11, c. 4 sub-c. 1:

A field Red; eleven twentieths field's width fess Black upon fly and hoist; nine twentieths field's width Gold upon fly and hoist; five twelfths field's width charge of Akatosh Black upon fly and hoist. Width of three feet; length of five feet.