Just for reference T20's take is
Imperial Expansion
Naturally, the Third Imperium did expand, its borders creeping out at a couple of parsecs a year. Most regions were assimilated bloodlessly through a combination of diplomacy, economic pressure and a reputation for fair and honorable conduct. Some worlds were eager to accept the protection of the Imperial Navy. And some resisted. This period of oftenforcible expansion is collectively known as the Pacification Campaigns, and is generally considered to have taken place in the period 76-120.
Thus the Third Imperium was involved in a number of naval, ground and peacekeeping campaigns at any given time in its early expansion. One of the most notable was the Arnaki Rebellion of 91-99, which drained Imperial resources considerably.
During this time, tension between the Second Luriani Protectorate and the Third Imperium increased. Negotiations broke down and the Imperial Archduke Ishargi, assigned to oversee the Gateway region, decided to strengthen his hand with a show of force. Leading a considerable fleet, Archduke Ishargi began a flag-showing tour through the region, intending to deliberately flout Luriani sovereignty to underscore his vast advantage in terms of strength.
However, in one of those flukes of history, the bulk of the Protectorate fleet was conducting exercises in the Rurur system when Ishargi’s force arrived. The resulting battle was a resounding defeat for the Imperials and Archduke Ishargi was killed aboard his flagship.
This sparked the Luriani War of 93-96. At first the Imperials, distracted by the Arnaki Rebellion and the minor insurrections it inspired, were unable to make much headway against the talented Luriani crews. However, in time the scales tipped more and more in favor of the Imperials and in 96 the Protectorate surrendered, accepting Imperial annexation without condition.
Incorporation of the Protectorate into the Imperium was not completed for another century. For no sooner had the Imperials broken Luriani resistance than they were sent to engage other foes; first the remnants of the Arnaki Rebellion and later a new empire deemed to pose a threat to the expanding Imperium.
In the far Rimward-Trailing region of Ley Sector lay the Sydymic Empire, a powerful interstellar state ruled by another minor human race. This was the empire of the Sydites, who had slowly and painfully climbed back onto the interstellar stage after rediscovering Jump drive in the last years of the Long Night, and now ruled parts of four subsectors. Skirmishes between Imperial ships and Sydite vessels had taken place since 73, but with the Luriani blocking Imperial expansion, it was not until about 100 that real conflict began. The next 20 years saw a series of small but bitter fleet clashes along the Sydite borders. The Sydites proved to be unimaginative but very determined fighters; their inferior technology compensated for by the fact that the Imperials were operating at the end of long lines of communications. When the Pacification Campaigns officially ended, the Imperials had made no real headway against the Sydites. Unwilling to go to the lengths required to crush them, the Imperials simply drew back a little and adopted a defensive stance, more or less ending the conflict. This had the effect of further curtailing Imperial movements towards Gateway Sector, which was still struggling though some very hard times.
The Imperials had been aware of the K’Kree for many years, and had even opened tentative communications, when the first official meeting of ambassadors took place on Mneonon in the year 103.
Imperial Consolidation
The Third Imperium continued to expand, albeit at a slower pace, after the Pacification Campaigns. This created considerable tension in other regions and the occasional war. Most notable among these was the Julian War of 191-195, which is notable mainly for the fact that it ended in an expensive stalemate.
One factor in the Imperial decision to seek a peace was the destruction of the Fornast and Ley sector naval depots by deep-raiding Julian fleets. These fleets brought the war to the Gateway region for a time, and significantly weakened the Imperial position in the region.
Nevertheless, the Luriani cluster was formally absorbed into the Imperium in 200-220. After a long period of negotiations, an acceptable settlement was reached and formalized by the Treaty of Daramm. This included the formation of a new Luriani Cultural Region administration to oversee the integration. This second LCR existed from 202-217, and then disbanded once its work was done. The Luriani culture was absorbed into the Imperium with little disruption.
