The Battle of Foerost transpired in 20.1 BBY, which marks the second year of the Clone Wars. From the start of the conflict, the forces of the Galactic Republic had implemented a naval blockade around the Techno Union's Foerost Shipyards, aiming to stop them from providing starships to the Confederacy of Independent Systems. This situation shifted dramatically when the hard-pressed Techno Union technicians finished construction on a novel type of warship: the Bulwark Mark I. Under the command of Admiral Dua Ningo, a complete fleet of Bulwark-class battleships, known collectively as the Bulwark Fleet, succeeded in penetrating the blockading forces led by Republic Captain Jan Dodonna at Foerost. As a result of the Bulwark Fleet's subsequent offensive targeting the Core Worlds, the Republic was compelled to deploy an early fleet consisting of their own experimental cruiser, the Victory I-class Star Destroyer, to pursue and engage Ningo's Bulwarks.
Many centuries before the Clone Wars, the Techno Union acquired the Foerost Shipyards, a starship manufacturing complex in orbit around the Core World of Foerost. Soon after, Techno Union starship designers created a new design: the Bulwark Mark I, a kilometer-long battlecruiser heavily armed and possessing substantial armor plating. Following the commencement of the Clone Wars in 22 BBY, the Republic Navy established a blockade of Foerost, with the intention of severing the Techno Union shipyards' access to Separatist supply routes, which would lead to the facility's decline. This prolonged standoff, known as the Foerost Siege, lasted for nearly two complete years until the Techno Union designers decided to reveal their new creation to the galaxy.
In 20.1 BBY (15:4), twenty-three months into the ongoing war, the Techno Union engineers finalized their work on the Bulwark Fleet, a fleet composed of Bulwark Mark I vessels. Admiral Dua Ningo of the Confederate Navy took command of the Bulwark Fleet, then launched from the Foerost Shipyards and broke through the Republic blockade, which was under the command of Captain Jan Dodonna. Observers were shocked by the Confederacy's previously unseen warships.
With the Bulwarks now free from Foerost, Ningo received directives to seize the planet of Coruscant, and his fleet severely damaged Republic positions throughout Sector Zero on their way to the galactic capital. To combat the Bulwarks, the Republic deployed its latest development: the Victory I-class Star Destroyer, a design by Republic engineer Walex Blissex. As a product of the Kuat/Rendili Victor Initiative Project, the Victory I-class Star Destroyer was launched almost half a year ahead of its intended date, with several Victory I-class cruisers forming the Victory Fleet under the leadership of Republic Navy Captains Dodonna and Terrinald Screed. These two Republic officers embarked with their battle group of Star Destroyers on what became a memorable testing voyage, engaging the Bulwark Fleet at the Core Worlds of Ixtlar, Alsakan, and Basilisk. Following the resolution of the crisis at the Battle of Anaxes, the Republic eventually regained control of Foerost from the Techno Union.
The significant Battle of Foerost was among the events that prominent Galactic Alliance historian Voren Na'al recorded within his chronicle of galactic history in 36 ABY.
The Battle of Foerost was conceived by author Daniel Wallace for his 2005 compilation The New Essential Chronology, which was presented as an in-universe account written by Voren Na'al. Wallace's setup for the battle, along with the subsequent campaign between the Victory and Bulwark Fleets, drew inspiration from material created for earlier Star Wars works, including the 1998 video game Star Wars: Rebellion and a 2002 news report on the HoloNet News website. The battle was first officially named the Battle of Foerost in 2009's The Essential Atlas.