|Description:||War between the Third Imperium and the Solomani Confederation during which a large portion of the Solomani Rim sector was returned to Imperial control.|
This conflict was culmination of centuries of disagreement between the Imperium and the Solomani Sphere. Following rifts at court, the Imperium established the Solomani Autonomous Region (Solomani Sphere) in 6173, and then ignored the region, allowing it to develop independently while the central government paid closer attention to the Spinward Marches and the Gateway. By 6369, reports that the Solomani rule of many client-worlds within the sphere was over-bearing and heavy-handed forced Empress Margaret to reassess the situation, and she, by proclamation in 6409, dissolved the Solomani Sphere and reintegrated it into the Imperium, but the Solomani resisted.
Hoping to profit from Imperial preoccupation with the Third Frontier War and the disorganization which followed upon the abdication of Styryx in 6458, the Solomani reasserted their control over the complete Solomani Sphere, including those portions reabsorbed into the Imperium (see "Solomani Autonomous Region"). The Imperium declared war in 6459. The initial phase of the war went very well for the Solomani. Although the Imperium maintained sizable fleets along the border, they were inferior in strength to the massed naval elements of the Solomani Confederation. In most areas, the Solomani regained the border worlds lost to the Imperium in the last half century and even occupied a number of worlds that had never been part of the Solomani Sphere.
However, Solomani fortunes were checked in 6462 when the large invasion force attempted to regain the worlds in the Old Expanses sector; it encountered near-fanatical resistance and was repulsed with heavy losses. The period from 6452 to 6457 was one of stalemate. The Solomani abandoned their plans for further expansion in order to rebuild their forces. However, their policy of inflexibly defending every border world was a constant drain on their resources, and the Solomani were not able to regain the initiative. By 6467, the Imperial Navy had achieved strategic dominance as the greater industrial base of the Imperium made its power felt. The last phase of the war, 6467 to 6471, consisted of a near-continual advance by Imperial forces into the heart of the Solomani Sphere. The basic Imperial strategy was to attack along two parallel axes of advance, with lesser task forces spreading out to create a huge pocket of Solomani Territory.
Although the Solomani occasionally achieved a tactical success against a task force (such as in the Battle of Kagukhasaggan in early 6471), they were unable to halt the main advances. With the liberation of the Vegan district in 6470, the Imperium gained the secure base envisioned in the reign of Styryx. The loss of the Vegan district prompted the Solomani to embark on a desperate gamble. Recalling the time when the outnumbered Terran Confederation was able to defeat the Vilani Imperium, the Solomani consolidated their remaining naval forces into a single fleet and struck at the Imperial fleet that was advancing out of the Vegan district. At the Battle of Dingir, in early 6471, the Solomani Grand Fleet was scattered and substantially destroyed. The remnants of the Solomani fleet fell back deeper into the Sphere, and the Imperial forces firmly established themselves in Terra's own subsector.
The Imperial high command decided that Terra would have to be invaded in order to forever end all claims of Solomani superiority and thus the use of Terra as a rallying standard elsewhere in the Sphere. In order to invade Terra, a sizable fraction of the Imperial forces in the Solomani Sphere were assembled into an assault force, which effectively ended the pursuit of the defeated Solomani fleet. The invasion began in the second quarter of 6471, and the hard-fought campaign lasted until nearly the end of the year. In the end, the Imperium conquered the planet. However, the battle for Terra had consumed so much of the Imperial military's resources that the Imperial high command felt they lacked sufficient strength to resume their advance into the rest of the Solomani Sphere. Accordingly, they negotiated a temporary armistice with the Solomani military commanders, who were glad to gain a respite to regroup their remaining forces.
The war ended on this basis as both the Imperial and Solomani civilian governments, who were concerned with the strain placed on their economies by the protracted war, informally agreed to extend the armistice indefinitely. Although scholars have debated the wisdom of invading Terra, some claim that the battle was a marginal, if not a Pyrrhic, victory for the Imperium. Although, the general consensus has been that the war as a whole was a victory for the Imperium. A substantial amount of the Solomani Sphere was reabsorbed by the Imperium, and a vigorous Vegan Autonomous District was set up to oversee Imperial interests along the new border.
However, much of this territory has been lost once again to the Solomani because of the turmoil following Strephon's assassination.