Here is the overarching fluff for my army.
The Westgate of Altdorf is an imposing stone construction located, unsurprisingly, at the westmost point of the Capital. As a possible entrance to the city and the first line of defense against a dedicated siege, the Emperor has appointed it with a permanent garrison. Located within the towers and gatehouse are spacious military barracks, and several cannon are mounted at the highest points.
Those who enter the Imperial Capital here, or through the Northgate, are liable for a tax; each person, wagon or horse entering the city is levied 1 gold crown per leg. A fair number of travellers actually have papers or medallions that exempt them from the duty, including priests and agents of recognised cults, members of certain Altdorf guilds, nobility, licensed coaching lines including their passengers, and any person granted special privilege in the name of the Emperor.
A team of eight to ten guards from the garrison enforce the law as well as collect any illegal weapons and armour. Generally, visitors are only allowed one hand weapon and dagger. All else is confiscated, unless the individual has specific authorisation given by the proper city authority. Those who possess such are given a receipt for their weapons, which they can collect once they leave the city.
As of 2522, the Commander of the Westgate is Grand Marshal von Breihaupt. von Breihaupt is a capable and talented man and, as a Grand Marshal of the Empire, may call upon any and all military assets he requires in pursuit of his duties to the realm. Whilst barracked in the Westgate, he and his men are not tied to it with a steel chain; von Breihaupt has, and will again, lead armies out of Altdorf to relieve or aid the other commanders and provinces of the Empire.