A very powerful warship compared to its contemporaries, the only real weakness of the Primus is its lack of fighter bay facilities. During the last days of the Narn-Centauri War, several Primus class battle cruisers were outfitted with outlawed mass drivers and were used in the planetary bombardment of Narn. 
The Primus' standard armament of two twin barrell heavy pulse cannons allow it equal ability to deal with capital ships and fighters. Despite this, without fighter support the Primus can be quickly overwhelmed by intense barrages from enemy fighters and a powerful Defence Grid. 
Since the Primus' introduction in the 2150s, the design underwent only one major upgrade. Starting in 2223 and proceeding through 2228, the ship's pulse cannon armament was upgraded to 8 Twin Barrell Heavy Centauri Pulse Cannons.
While slightly older than the Vorchan class cruiser it was nevertheless the most powerful warship of the Centauri fleet and in the glory days of the Republic was a symbol of fear for many of the younger races, save of course the Minbari, a race even the Centauri Republic never attempted to challenge.
Centauri fleets tend to be composed entirely of Primus-class ships. To make up for their lack of fighter escort, they attack in a combat box composed of multiple, staggered wedge formations. This allows their ships to concentrate firepower on targets directly in front of the fleet while simultaneously protecting one another from fighter attack through the use of interlocking fire. Thus, Centauri formations are only truly vulnerable to attacks from the rear.
In combination with the Vorchan class medium warship, the Centauri adopt tactics reminiscent of the Earth Alliance, which employs Nova and Hyperion-class ships, with the Primus-class cruisers providing fire support for the Vorchans while fighters screen the fleet and attack vulnerable targets en masse.
- Unnamed vessel destroyed in 2245 in the Epsilon System in a surprise attack over Babylon 5 by a Narn heavy cruiser.
- Unnamed vessel destroyed over Babylon 5 by a G'Quan class heavy cruiser after a failed blockade of Babylon 5.
- Unnamed vessel destroyed over Babylon 5 by the Defense Grid after threatening to attack the G'Tok Narn cruiser.
- Unnamed cruiser blown by a bomb beside Babylon 5 in 262 in an apparent assassination attempt against Londo Mollari.
|The following is based on The Mongoose Publishing RPG books and contradicts canon sources.|
|The following is based on The Agents of Gaming Strategic Game and contradicts canon sources.|
Sources regarding the size, weaponry, complement, etc., of the Primus Battlecruisers varies widely not only per the different roleplaying / wargame publishers but also between different editions. The specifications from non-canon sources are as follows:
- Length: 455 m
- Crew: 602
- Weapons: 4 battle lasers, 8 twin particle arrays
- Auxiliary Craft: 12 fighters, 2 shuttles
- Service Date: 2202+
Babylon 5 the Roleplaying Game's Ships of the Galaxy
- Crew: 201
- Weapons: 6 battle lasers, 13 particle arrays, 4 Mk 1 interceptors
- Auxiliary Craft: 24 Sentri medium fighters
Babylon 5 the Roleplaying Game's The Centauri Republic Fact Book
- Crew: 99
- Weapons: 2 twin-linked battle lasers, 8 twin-linked particle arrays
- Auxiliary Craft: 12 Sentri medium fighters, 2 shuttles
Babylon 5: A Call to Arms (Game)'s Fleet Lists
- Crew: 65
- Weapons: 1 battle laser, 4 twin-linked ion cannons
- Auxiliary Craft: 12 Sentri medium fighters
- Service Date: 2195+
Behind the Scenes
- There are some contradictions between data regarding the Primus's crew complement, it's fighter carrying capability and weaponry contained in two sources: The Official Guide to Babylon 5 (CD ROM), a canon source, released by Sierra Entertainment and unreleased computer game (also by Sierra) Babylon 5: Into The Fire, which canon status is not certain.
- The Official Guide states the cruiser lacks fighter bays (In fact the cruiser was never seen to launch any fighters), its crew complement is consisting of 212 crewmembers and it's armed with X-Ray Lasers as well as 4 Heavy Laser cannons and 2 Twin Particle beams, while archived website of unreleased PC game Into The Fire states the cruiser is capable of carrying 14 Sentri medium fighters, its crew complement is consisting of 72 officers and 1,352 enlisted personnel and it's armed with 8 twin heavy pulse cannons.
- Babylon 5 the Roleplaying Game: The Centauri Republic Fact Book
- Babylon 5 the Roleplaying Game: Ships of the Galaxy
- Babylon 5: A Call to Arms (Game): Fleet Lists
- Babylon 5 Wars: War of Retribution: Atlas of the Narn/Centauri War
- Babylon 5 Wars: Ships of the Fleet
|Centauri Republic Ship Classes|
|Primus-class Battle Cruiser · Vorchan-class Medium Warship|
|Sentri-class Medium Fighter|
|Primus-class Liner Variant · Liner · Transport · Atmospheric shuttle · Crew Shuttle|
|Space station · Shipyard · Blockade mine · Perimeter mine|