The Magog-Commonwealth war was a brutal conflict fought between the Systems Commonwealth and the Magog. The war dragged on for years until the Treaty of Antares was signed ending the conflict. What the Commonwealth didn’t know was that the Magog never intended to win the war. The war had secretly been instigated by the Spirit of the Abyss, as part of its plan to leave Known Space vulnerable to the Magog World Ship.
At the height of its power the Systems Commonwealth spread across 3 galaxies and had enjoyed 1200 years of peace. That peace was shattered on CY 9766 when the previously unknown Magog launched a surprise attack on Brandenburg Tor. Brandenburg Tor's home guard fought bravely but outnumbered a hundred to one they were eventually overrun. The planets 3 billion inhabitants were all killed.