The Imperial Civil War, also known as the "Lippstadt Rebellion" or "Lippstadt Conspiracy," was a conflict fought in Imperial Year 488 between the forces of the Lippstadt Alliance (representing an Empire establishment composed mainly of high nobles) and those commanded by Marquis Reinhard von Lohengramm.
In Imperial Year 487, Kaiser Friedrich IV suffered a heart attack and died, having failed to assign a successor to his throne. The question of which of his three young grandchildren would ascend to the position led to a struggle amongst various parties who sought power within the Empire:
- Count Reinhard von Lohengramm, who initially had sought to overthrow Friedrich purely as a matter of justice or revenge (Friedrich had taken Reinhard's sister Annerose as a consort several years prior). His vision seemed later to have expanded, however, to include control over the entire Empire, and possibly all of Terran-controlled space. Lohengramm supported Erwin Josef II, the 5-year-old son of Princess Christine and the late Prince Ludwig. (LOGH: "Into the Eternal Night", "Cool, Clear Artificial Eyes", "New Trends")
- Marquis Klaus von Lichtenlade, who had served under Friedrich as his chief of staff and secretary of state. He too supported Erwin Josef, because the latter's lack of a strong parental influence would make the child easy to control.
- Duke Otto von Braunschweig, a high noble who had married the Kaiser's daughter Amarie. He supported his own child, 18-year-old Elisabeth, for obvious reasons.
- Marquis Littenheim, another noble, who had married the Kaiser's other daughter Christine. He too supported his own daughter, 16-year-old Sabine.
After consulting with his advisers, Lohengramm chose to ally with Lichtenlade, and together they were able to effect the ascension of Erwin Josef to the throne that same year. Coinciding with this event, the then-Count Lohengramm was given the title of Marquis.
Braunschweig, Littenheim, and other high nobles—outraged by Lohengramm's increased stature within the Empire, as well as their own reduction in power—forged an alliance of their own to fight the "Lichtenlade-Lohengramm Axis." (LOGH: "New Trends")