The earliest battleships were designed to meet the very specific needs of their time, which was not ship-to-ship combat, as fleet planners did not expect the outer colonies to possess any sizable naval resistance. Rather, battleships were purpose-built to destroy orbital and planetary defences, and to partake in planetary bombardment roles. Fleets of battleships had little purpose except to bring unruly planets into line with the threat of annihilation from orbit. Since vessels only expected resistance in the form of satellite-based weapons platforms or (more rarely) planet-side weapons, early naval designs emphasized heavy frontal armor and forward-facing heavy lasers, with corresponding penalties to propulsion. Such designs enabled battleships to dish out the largest amount of damage to largely-immobile defence platforms, while being relatively unscathed by the return fire.
Such design philosophies were sufficient in the early Terran era, when space was the sole domain of a single power. But the galaxy was too large for a single watchful eye, and eventually, whether through neglect or exhaustion, other powers rose. Though these nascent nations stood united in opposition to Terra, their actions towards the less developed worlds was far from benevolent. With fleets of their own, they too spread to stake their claim over the various worlds. The tools of war were unchanged, and only the flags flown were different.
The first purely naval battle was fought between two fleets of much different size. Even with the advantage of numbers, the Terran fleet was unable to inflict a total defeat on the enemy forces. Though at the time much blame was placed on the commanding admiral, the modern consensus is that early battleship design was far too ill-suited for fleet-to-fleet combat. Forward-facing heavy lasers directed a devastating beam, but only in a extremely narrow firing arc. Against a mobile target, one that could maneuver in any direction in 3D space, this was a severe handicap. The problem was compounded by the comparatively slow charge times for the weapon and the poor maneuverability of the battleships, especially in performing spatial rotations. Taken together, the battleships could not track and hit moving targets with much reliability.
The end of the late Terran era was marked with several major fleet battles, none of which had any conclusive victor. Very rarely was the balance of powers changed in any significant way purely though the use of naval force. Despite the failure of battleships as decisive weapons, the concept of naval power retained its place in popular imagination as symbols of national power. Later technological advancements would vindicate the importance of the battleship as mighty weapons of interstellar war.
Part II: The Age of Contention