Castle Dour

Located in Solitude, it serves as outpost to the Imperial Legion during the Skyrim Civil War. General Tullius resides within, along with his second in command, Legate Rikke. Both command the Imperial Forces in Skyrim.

Castle Dour Dungeon
The Castle Dour Dungeon is the dungeon inside of Castle Dour. Those who commit crimes in Solitude are sent here to serve their sentence.

Emperor's Tower
The Emperor's Tower is a wing of Castle Dour, reserved for the Emperor of Cyrodiil, when he or she visits Skyrim's capital, Solitude. Lavishly furnished, the tower contains many valuable items. The Solitude Windmill is connected to this wing.

Battle for Solitude
Siding with the Stormcloaks during the Skyrim Civil War, the Dragonborn sacks the tower with their fellow Stormcloaks, as their final plan mobilization about the Imperial Legion.

Breaching Security
Gaius Maro is scheduled to patrol Emperor's Tower and Castle Dour, day and night, on Morndas', surveying the area for suspicious activity before Emperor Titus Mede II's arrival in Skyrim aboard The Katariah. The Listener of the Dark Brotherhood might have executed him in one of these two locations and planted an Incriminating Letter on his corpse, as a warning to Commander Maro.

To Kill An Empire
Impersonating the Gourmet, the Listener of the Dark Brotherhood plans to assassinate Emperor Titus Mede II. The Emperor visits Skyrim to attend to the business of the civil war, as it is believed that his cousin, Vittoria Vici, was assassinated due to the conflict. However, this was incorrect, as she was executed by a member of the Dark Brotherhood. He resided within Castle Dour, and the Listener, disguised as the Gourmet slipped the ultra-poisonous Jarrin Root into his stew. Receiving a tip from Astrid that an assassin was coming to kill the Emperor, Commander Maro replaced the Emperor with a decoy who was killed instead. As the Listener tried to flee the Castle, agents of the Penitus Oculatusintercepted them, failing to remove the Dark Brotherhood member who subsequently escaped.

Bugs
When exiting the dungeon after serving time you might be immediately attacked by a troll. This is dangerous for low level characters as the cause is not yet known.

Related Quest

 * Battle for Solitude - At the end of the Stormcloaks questline.
 * To Kill An Empire - A Dark Brotherhood quest.