The Human / Romulan war was Humanities first interstellar conflict after more than forty years of total peace. Thus, while the Romulans began the war with a well tested fleet of purpose designed combat vessels, the Humans where trying to hold them back with converted merchant vessels augmented by the occasional ship bought from an alien government. From the first day of the war it was obvious that a new class of warships was needed, ships that where larger, faster and more powerful than any which had preceded them. Work began at a feverish pace early in 2156, and by mid 2158 the first of the new Daedalus class was launched.

The designers where urged to be daring, and they certainly took this advice to heart. Instead of the integrated hull form which most previous ships had possessed, the Daedalus class was the first design which featured a multi-hulled configuration. The engineering section was a cylinder six decks tall which housed the ships heavy engineering equipment - the warp core, structural integrity and inertial damper field generator systems, shield generators, hangar bays, impulse drive, etc. This hull was connected by a two deck neck to a spherical primary hull which housed the ships main weapons, control areas and provision for the crew. The Daedalus class was intended to remain in space for up to a full year with minimum outside support, far longer than any pervious design. The accommodation standards where thus much improved compared to the ships which began the Romulan war; the senior officers had individual rooms, while all enlisted personnel had barracks style accommodations. Considering that contemporary vessels slept everybody below the rank of Lieutenant Commander in hammocks hung wherever there was room, the Daedalus represented a quantum leap in luxury.

Primarily a combat vessel, the class was fitted with four laser cannon of the heaviest type in service and a magazine of twenty four fusion missiles. Combined with her high speed and enhanced shield capacity, the Daedalus was considered equal to any four Romulan warships. In service they proved exemplary, rapidly acquiring a fearsome reputation on the front lines. By 2159 the rapidly growing Daedalus fleet had turned the tide in the war, and by the end of that year they where routinely striking deep into Romulan home territory. The Romulans, faced with a war now fought almost wholly on their own territory, sued for peace in 2160.

When the United Federation of Planets was formed in 2161, the constitution called on members to supply the newly formed Starfleet with ships until purpose-built vessels could be constructed. The pacifist Vulcan's where reluctant to devote resources to what they considered a military force, but the Humans had no such qualms; of the fleet of seventy Daedalus class vessels in service in 2161, they turned over no less than sixty of these to Starfleet. With Starfleet assigned a major scientific and exploratory role in addition to its secondary military mission, this bold move bought the Humans a huge stake in the future of the Federation. Virtually every exploratory mission, every first contact, every new scientific discovery made in the first eighty years of the UFP was made by Daedalus class starships under Human command and carrying wholly Human crews. Several Daedalus class ships where lost during their exploratory missions for Starfleet. The USS Essex (NCC-173), under the command of Captain Bryce Shumar and first officer Steven Mullen, was lost to an electromagnetic storm while investigating a class M moon orbiting Mab-Bu VI. The USS Archon was lost when its crew was absorbed by the entity known as Landru on the planet Beta III in the system C-111.

The Daedalus class USS Horizon visited Sigma Iotia II in 2167, resulting in massive cultural contamination of that planet. The huge number of such first contacts, together with the planting of colonies and exploratory work, resulted in a heavy pro Human bias in the evolving structure of the Federation itself, and most especially within Starfleet. This bias endures even to the present day.

The first of the Daedalus class vessels reached the end of its hull life in 2188. Initially it was planned to conduct a major overhaul on the hulls of the ships to extend their lives a further twenty years, but with a lessening in tensions during this period it was decided that Starfleet needed fewer heavily armed ships in service. The number of Daedalus class ships was allowed to gradually fall as ships reached the end of their hull life and retired. Initially it was planned to retire the crusier-type altogether in favour of large numbers of smaller, more manoeuvrable vessels. But in the end it was decided to put most of the Daedalus fleet into mothballs against possible future need. The last one hundred ships where placed in storage in 2196.

As the Daedalus ships fell behind the state of the art and became gradually less useful even as a reserve force, Starfleet began to find other uses for them. One was retained for the Fleet Museum, where it remains to this day. Some thought was given to refitting the remaining ships and using them as cargo carriers, but this plan was abandoned. Another plan to sell the Daedalus fleet to alien governments was also abandoned when the Prime Directive was established in 2225. Thirty of the ships where used in live fire exercises - one achieving a degree of fame as the first vessel destroyed by a phaser bank during the development of that weapon in the 2250's. The remaining ships where scrapped between 2250 and 2260. Today the only Daedalus class vessel in existence is the single example still in the fleet museum.