Fall of Caliban
The Fall of Caliban was the capture of the United Empire of Earth controlled Caliban system by a Vanduul clan in 2884. The actual battle and capture only lasted two days (7 to 8 July 2884) and was accompanied by an overhasty organized evacuation of 'most' of the system's inhabitants. Later attempts of the UEE to re-establish military control failed and ended with the abandonment of Caliban in the same month.
Siege and capture of Caliban
The invading Vanduul forces surprised the UEE forces. The defending UEE Navy's 88th Squadron was annihilated (only one crewman survived) protecting civilians trying to flee the system from the attacking Vanduul fleet in the first two days. The Vanduul clan used a Kingship. It was the last sighting of such a ship until 2945.
On 9 July reinforcements of the UEE entered the system and fought against the intruders, but after heavy casualties, the system was finally abandoned on 23 July 2884. Crion and all other planets were harvested by the Vanduul and are still under their control.
The 2946 holovid series Lost Squad is based on this event.