The Oberon Confederation was born in the aftermath of the 2773-2775 war between the Lyran Commonwealth and the Rim Worlds Republic (part of the Amaris Civil War). Much of the Rim Worlds were annexed by the Commonwealth, but the most distant ones were not. Originally comprised of just 3 worlds, it expanded in the years that followed, as Lyran interests lay elsewhere. Never a violent or expansionist power, the people of Confederation were content with just surviving the rigors of Periphery living.

Fast forward a couple of centuries to the years 2940. The 3rd SW was in full swing, and on the FWL world of Graham IV one Colonel Hendrik Grimm decided he had had just about enough of Lyran High Command. After months of hard fighting for control over Mitchell Industries' facilities on the planet, he could only watch as more and more Marik reinforcements arrived - while he got none. He gathered the remnants of the 6th (his own regiment) and 5th Lyran Regulars and departed Graham. Knowing they would find no refuge in the Commonwealth, they headed for the Periphery.

When reinforcement finally arrived on Graham about a year late, the Lyrans found it to be fully in Marik hands, and another major campaign developed. It took two years to recapture what Grimm had already conquered - and when the Lyrans finally succeeded, they found the Marik's had evacuated everything of industrial value. The Lyrans blew up some empty factory buildings and went home. It was hailed as a great victory on Tharkad. There was some talk of searching for Grimm, but he was assumed dead and buried on Graham.

Meanwhile Grimm wasn't having much success in the Periphery. Details are scarce, but for years he and his people wandered along the Rim, stirring up trouble and learning just how hard life out there can be. Eventually they winded up on a virtually unknown world within the Oberon Confederation: Henry's Star. How he came to learn of the system no one knows. Perhaps it was chance, perhaps he listened to an old legend and decided to risk it all on a final gamble. On the world called 'Crater' he found an old outpost of the Rim Worlds Republic, still inhabited by the descendants of the people abandoned there generations ago. He either conquered them - or persuaded them to join him. No one knows for sure. However it went the damage caused was very minor, if there was any at all.

It matters not. What matters is that Grimm hadn't yet found safe haven, but he at least had a base from which to operate. Desperately short on resources he started raiding the Inner Sphere - or more specifically, the Trellshire. It worked only too well, and Grimm gained a massive influx of slaves and worldly goods. Using his newfound success as a pirate as a springboard, he attacked Oberon VI and force it to submit to his rule (shortly prior to 2955). He then proceeded to alternate between expanding his little "Empire" and raiding the Commonwealth. He moved his flag to Oberon, and did his very best to limit knowledge of Crater, which became something of a "treasure planet".

Eventually Tharkad took notice. Garrisons along the rim were reinforced, as much as was possible given demands elsewhere. This just caused the Oberon pirates to raid ever deeper into Coventry and Trellshire. Punitive raids were then launched against Oberon, but the Grimm was never home when they came calling. Finally Lyran Intelligence was able to track him down, and the bulk of the 3rd Lyran Guards under Colonel Melissa Musgrave were dispatched to deal with him in 2978. They were never heard from again: More than two heavy mech battalions and supporting assets were lost, along with a Star Lord, a Fortress, an Overlord, three Unions, and support ships. The operation was hastily classified and all mention of it buried forever.

Col Musgrave was not the only commander to die upon Crater. She took the aging Hendrik Grimm with her - the man was over 80 at the time, but still commanded from the front. He was succeeded by his Son Hendrik II Grimm. But the battle had taken its toll, and succession already leads to unrest in these minor realms ruled by a single strong leader. Hendrik II eventually consolidated his power base and became a pirate king like his father, but he was smarter, and spread out his raids more and sought to make profit through trade also. He also expanded his influence into neighboring realms, annexing some, making others his vassals - and allying with both the Greater Valkyrate (through marriage between his son, Hendrik, and a princess of the Valkyrate) and the Elysian Fields.

By 3002 the Oberon Confederation is a fairly large and powerful Periphery realm. It's certainly much more powerful than what the Inner Sphere realizes. The Confederation is still ruled by old King Grimm II from his royal hall on Oberon VI. He has several children. His oldest, Hendrik, is married to a woman of the Valkyrate. By all accounts this Hendrik, who is a skilled mechwarrior, will be crowned King Hendrik II Grimm when his father passes.

The Confederation has about 10 core worlds, plus an equal number of vassal (minor single or multi-system Periphery states). It is also allied to the Valkyrate (6+ worlds) and the Elysian Fields (just under 10 worlds).