Juno is an naval fortress originally built in the Dark Ages, but continuously renovated.
During the Middle Ages a navy called the Knights of the Sea was established in the naval fortress to deal with piracy in Ordis, which has been known as a prosperous city since antiquity. The Order fought many large-scale naval battles against the pirates near the coast of Ordis.
During the Erebonian Civil War, Juno served as the headquarters of the Noble Alliance. After the Imperial Army of Erebonia and Rufus Albarea of the Noble Alliance concluded on a ceasefire, the Old Noble Alliance spearheaded by General Aurelia Le Guin, commander of the Lamare Provincial Army, held the castle until August S.1205. Their force at the time consisted of 50,000 soldiers, enormous airships, enough supplies to extend their siege for 3 years and fully equipped antiaircraft artillery. Even the Imperial Army was perplexed on how to deal with the situation.
In March 22 S.1207, the fortress was leveled by Reverse Babel as a result of neither Erebonia or Calvard responding to the Supreme Leader's proclamation that they join its Crossbell Unified Nation by noon. A massive whirlpool was all that was left of the fortress; fortunately, no one was stationed at the fortress when it was destroyed.