The battle was four years after the start of the Earth-Romulan War, fought within the 83 Leonis B system, and in orbit of its fifth planet, Cheron. Cheron was a Romulan military base and shipyard, and was being used as a staging ground for an invasion of Earth and the other Coalition of Planets systems, under the orders of Admiral Valdore. A Starfleet task force of 24 ships led by the Enterprise and commanded by Jonathan Archer attacked the staging grounds, taking on 81 Romulan ships.
The first wave of the battle was fought in orbit above Cheron, resulting in roughly 50 percent losses to both sides, with the Romulan forces, under Admiral Tal, retreating when reinforcements of Klingon and Andorian freebooters commanded by Kolos and Shran respectively arrived. The Romulans regrouped, and warped back in to attack, but were slowed by Trip Tucker, undercover on the Romulan flagship, causing the failure of the fleet's antimatter containment systems, resulting in the destruction of three ships. The fight was joined at impulse, with the more powerful Romulan ships on the verge of victory when a wave of Vulcan, Andorian and Tellarite ships arrived and swung the battle in the Coalition's favour, but allowing the Romulans to retreat back to home territory under direct orders from Praetor Gileus. (ENT novel: To Brave the Storm; ST reference: Federation: The First 150 Years)
- This is somewhat contradicted by Last Unicorn RPG module: The Way of D'era: The Romulan Star Empire which states the battle was brought about through Human trickery which resulted in a Romulan fleet being lured into a trap where they were obliterated through the use of overwhelming force that was warped in at the last moment.
It was during this battle that Terran forces were able to turn the Romulans back into their own territory and prevent the invasion of Earth. (TOS - My Brother's Keeper novel: Republic; ENT novel: To Brave the Storm)
Additionally, a determined Earth Command strike force warped in close to the planet during this battle, and managed to destroy a crucial Romulan supply depot, further crippling the Romulan forces. Among the members of that force were Aaron Stiles, Michael Hagedorn, and Hiro Matsura. (ST novel: Starfleet: Year One)
Following the battle, some commanders in the United Earth forces wanted to continue on pushing the Romulans back all the way to Romulus and deal them a death blow which would destroy all their shipbuilding facilities and rule the Romulans out as a major threat. However, cooler heads prevailed and it was decided that as the Romulans were a proud people, total defeat would humiliate them, and would lead to future conflicts. Instead it was decided to leave the Romulans dignity intact. (TOS - My Brother's Keeper novel: Republic)
Soon after the Battle of Cheron and the ending of the war, the United Federation of Planets was formed, and along with it was created the Federation Starfleet, presumably as a retooling of the old United Earth Starfleet.
- According to ST novel: Starfleet: Year One, the first starship created specifically for the new incarnation of the fleet was the USS Daedalus, commanded by Hiro Matsura, with veterans of the battle of cheron passionately argued over the direction the new Starfleet should take, whether it should be primarily scientific or militaristic. However, ENT novels: Beneath the Raptor's Wing, To Brave the Storm states that Daedalus-class ships were created by Earth Starfleet before the NX-class was designed.
Even into the 24th century, the battle remained an intense embarrassment for the Romulans, which, according to Alidar Jarok, would be retributed by "the new leaders" on Romulus, who "vowed to discard the treaty and claim the Neutral Zone," with Nelvana III being the first step. (TNG episode: "The Defector")