Serpent's Hold

Description
Situated on the Isle of Deeds, east of the Cape of Heroes, the fortress of Serpent's Hold stands as a building symbolising the principle of Courage. Its mighty walls strengthen the courage of its fighters and allies, while putting fear into the hearts of the enemies of the keep. The Order of the Silver Serpent has the command over the fortress, and adventurers of all kind are welcome to test theit skill in a sparring match.

The fighters of Serpent's Hold are the best in all of Britannia, and train many recruits in the ways of fighting and war. Also the best weapons and armours are produced at Serpent's Hold. Serpent's Hold is also known to house the Eternal Flame of Courage and the Bell of Courage, two items of high symbolical value. As long as Serpent's Hold stands, Britannia will defend itself from every kind of threat.

History
Serpent's Hold was built before Ultima IV. Throughout the ages, Serpent's Hold didn't change much. In Ultima V, one of the Shadowlords was defeated there. After that time, some functions were outsourced to buildings around the fortress, but otherwise, Serpent's Hold stayed the same in Ultima VI and Ultima VII.

In Ultima IX, Serpent's Hold was destroyed. (Many fans consider the events in Ultima IX as non-canon).

Ultima V
...

Ultima VI

 * Amanda :tavernkeeper.
 * Caradon :fighter.
 * de Hugh :fighter.
 * Gherick :armourer.
 * Koranada :knight of the order.
 * Lady Tessa :lady of the keep.
 * Lord Simon :lord of the keep.
 * Loubet :trianer.
 * Morchella :pirate.
 * Sentri :fighter, can join.
 * Seggallion :adventurer, can join.
 * Shubin :cook.

Ultima VII

 * Denton :tavernkeeper.
 * Jordan :shopkeeper at Iolo's Bows.
 * Lady Hanne :provisioner.
 * Lady Leigh :healer.
 * Lady Tory :empathic nobewoman.
 * Menion :trainer.
 * Ricky :Lady Tory's child.
 * Sir Hoffre :captain of the guard.
 * Sir John Paul :lord of the keep.
 * Sir Pendaran :a knight.
 * Sir Richter :blacksmith and second-in-command.

Serpent's Hold in Ascension
In Ascension, Serpent's Hold was destroyed by the Guardian, sunken under the sea. The ruins still housed the Bell of Courage, guarded by a fighter. The Avatar had to retivre it from the ruins.

Trivia
(More info is available here: Real-Life references and Easter Eggs).
 * In Ultima VII, almost all of the inhabitants resemble the crew of Star Trek: The Next Generation. (Especially noticable with Lady Tory)