The First-Generation Colonial Battlestars were the principal warships first deployed at the opening stages of the First Cylon War. Weaknesses in this design led to the rapid construction and deployment of the COLUMBIA-Class battlestars.
Weaknesses were the lack of defensive armament and the exposed nature of the landing bays. Unlike the COLUMBIA class, the landing bays had a force-field contained atmosphere. Cylon attacks on these ships targetted specifically the force-field generators resulting in explosive decompression of the bays.
The first twelve first-Generation battlestars: BSC-1 COLUMBIA (representing Aries), BSC-2 SOLARIA (representing Canceron), BSC-3 GALACTICA (representing Caprica), BSC-4 ATLANTIA (representing Picon), BSC-5 CEREBRUS (representing Geminon), BSC-6 ACROPOLIS (representing Libron), BSC-7 PACIFICA (representing Sagittarian), BSC-8 ILLUSTRIOUS (representing Leonis), BSC-9 PEGASUS (representing Aquarion), BSC-10 GLORIOUS (representing Tauron), BSC-11 ATHENA (representing Virgon), and BSC-12 RYCON (representing Scorpio) found themselves taking on much more than anticipated during the first Cylon War. Most of them were destroyed or so severely damaged, that the new COLUMBIA class had to be rapidly built and deployed, taking into account the lessons hard-earned. After the armistice, the four remaining battlestars of 'the original twelve' were swiftly decommissioned and scrapped – their names being carried over to the newer ships – much more than twelve.