Caer Brennnan was the name of first the fortress, and then the city that sprang up around it, at the heart of Damryn. It was the seat of power for the nation and for the Realm, and the home to the Throne of the High Kings of Damryn.
The fortress was built by the legendary Tewdyr, the first High King of Damryn, at the dawn of the unification of the nation. The city would grow around the seat of power over the centuries to become the capital, and the largest city in the human world. With its mighty stone wall surrounding the city, and the fortress guarding the easiest avenue of assault, it was considered the peak of human architectural achievements, and over the centuries received the attention and work of specialists from all over the Realm.
Caer Brennan was considered an impregnable fortress, and for over five hundred years it was never successfully assaulted. It was the last territory formally conceded by Damryn to the Legion in the Fall, and the site of the nation's ultimate defeat before the flight by the survivors to Andermark. The battle for Caer Brennan was the third-biggest battle in the war, after the Last Stand of Starkholm and the first battle of the Alliance on the shores of Carnthor.
Before it was lost, Caer Brennan was the centre of travel, commerce, politics, and military might for the whole of the Realm, and consequentially for the whole of humanity. It was a mighty, wealthy city, and was said to be the most prosperous and provide the highest quality of life of any city outside of Calavria.