Generally agreed to be the largest space battle of all time, the battle of the line was fought between the naval forces of the Imperium and the invading fleet of the Ancient enemy. In the five hundred years since the battle was fought many details have been lost to time or become mythologized but the significance of the battle is not in dispute.
Prelude
Near the end of the Dyastrin dynasty mismanagement and corruption had led to a general breakdown of authority throughout the Empire. Noble houses rushed to fill the vacuum and warred with themselves as well as the Empire. During this time period Earth itself even fell to rebels briefly though a plea for help from the ailing Empire led to House Vira forming a Coalition of nobles to restore order on the home planet.
Into this vacuum the ancient enemy appeared, initially their return was unheralded and few even noted the growing chaos on the outer rim. Politics continued as normal with House fighting House and the Empire teetering on the edge of collapse, meanwhile the outer rim burned.
It was not until a massive alien invasion fleet began tearing through the mid rim planets that the majority of the Empire began to take note. However the Emperor proved incapable of rallying the feuding nobles to his side and was at this time of ultimate crisis came to his untimely demise at the hands of Grand Admiral Faith [[1]].
The Grand Admiral was married to the son of the deceased Emperor and she claimed to be ruling on his behalf. Few expected this arrangement to work and whispers of civil war were in the air. But with the support of the then powerful Church faction led by her cousin Anyanka and with House Vira (considered by most to be the most powerful house at the time) willing to temporarily put their rivalry with the Rozenburgh’s aside to the surprise of most the nobles and Imperial forces rallied to the Grand Admirals side.
The battle Details of the battle itself are sketch both because of the length of time which has passed and because there were so few survivors.
What is agreed upon is that virtually every dreadnaught in the Empire, those controlled by the nobles and by the Empire itself were at the battle as was virtually every other ship capable of military service. On the side of the ancient enemy there were even more ships, as theirs were generally smaller but more plentiful. Estimates as to the number of vessels on both sides involved in the battle range from 2000-10000.
The battle is known to have opened with a massive assault by the enemy against the center of the Imperium battle formation in an attempt to quickly silence the dreadnaughts. Initially the assault was largely successful and dozens if not hundreds of the massive ships were quickly destroyed by weapons fire and ramming from the enemy. The tide of the battle was eventually turned by an experimental weapon which was secretly deployed by the Grand Admiral. A massive mobile space station brimming with weapons and supposedly impervious to enemy action has been secretly developed and built the empire over the preceding decades, originally it was intended as a means of securing hostile systems from the Noble Houses, but in the Battle of the line the prototype would prove effective against even the ancient enemy. With the space station taking up the slack from the many fallen dreadnaughts the line held and the enemy was decimated over several hours of bloody fighting. However the space station would not prove invulnerable and near the end of the battle was finally brought down in a massive explosion as dozens of enemy vessels sacrificed themselves to buy time for their comrades to escape. Aboard the space station was the Grand Admiral who went down with her ship.
With both sides having taking massive casualties and their fleets in disarray the Imperium could only be said to have won a tactical victory as the enemy fled the field. It was believed this would only be the first of many bloody battles.
In the leaderless Imperium fleet Paul Vira assumed command and declared his wife Phonecia Dyastrin (daughter of the late Emperor) Emperess. Overruling the advice of a hastily assembled war council made up of the remaining Houses Vira led the fleet in pursuit of the enemy, only to find they had vanished. So it was the battle of the line would come to be the decisive battle of the entire campaign and this tactical victory achieved by the thinnest of margins would come to occupy an almost mythological place in Imperial culture.
Aftermath
Casualties among the Imperium fleet are believed to range from 50%-70% this devastation of the Noble House’s fleets coupled with the perceived need for centralization should the ancient enemy return enabled Vira to enact reforms his Dyastrin predecessors could only dream of. The powers of the noble houses were curtailed; military power was concentrated in Imperial hands and peace returned to the shattered Empire.
Paul Vira would continue to reign in his wife’s name until his natural death decades later, rebuilding the Empire and always strengthening its defenses lest the enemy return. He would never formally assume the title of Emperor, though his son would and that would bring about the formal end of the Dyastrin Dynasty and the beginning of two centuries of Vira rule.