Attempted to make some corrections. The head seemed to be where the problem was, so I pointed it in another direction and refined it some.
The President's Battlestar, from Piscerion. My notes say she was constructed after Columbia to improve on the concept, and as a result she's the template for the other battlestars constructed (Columbia was a kind of outline). Whereas the Columbia was perhaps too little on the concept, Atlantia is too much, and swallowed a significant amount of resources and funding to construct- moreso than any other Battlestar. Only the Solaria approaches Atlantia's size.
Because of her advanced C&C capability she was designated as flagship of the entire colonial fleet. Because of her role as flagship, she was designated as the President's envoy during the peace treaty at Cimtar. AS the largest target and clearly the fleet command ship, she was the first battlestar targeted by the Cylon raiding force... and the first battlestar destroyed at the conference. President Adar died with her, his last words being "How could I be so wrong?!" in regard to believing the falsehood that peace could be made with Cylons.