The mobile fortress "City of the Divine Eagle".
An unprecedented city in the sky, an impregnable stronghold, a masterpiece of construction and shipbuilding, a spiritual symbol of the Royal Army, evidence of divine favor for Charlemagne... among a whole mess of nicknames, only "the ultimate manifestation of battleship diplomacy" truly hit the nail on the head in describing the nature of this floating rock in the sky.
Generally, fortresses exist as defensive structures. If a fortress could move on its own, it wouldn't be much different from a battleship.
Solid as a rock in defense, swift in mobility, powerful enough to destroy any obstacle with its firepower—that's exactly what a battleship is. No matter how the times and technology evolve, when evaluating the performance of a battleship, the first thing people consider is comparing these three parameters with its peers. The City of the Divine Eagle was no different.
