Koltaari is a planet, best known for being in disputed space between the United Federation of Planets and the Romulan Star Empire, leading up to the Tomed Incident. It was of strategic value to both groups due to its location and also its vast untapped resources of dilithium, pergium, cormaline, and bilitrium.
The presence of a dampening field on the planet attracted the USS Enterprise-B as the Koltaari did not seem to possess the technology to create one. A landing party on the planet soon discovered that the dampening field had been created by Romulans as a precursor to invasion.
In 2311, Koltaari was briefly occupied by the Romulan Star Empire, who hoped to use Koltaari's resources for an imminent war with the Federation. The Koltaari were used as slave labor in order to mine the resources.
The invasion fleet consisted of three D'Vorix-class starships and the Ivarix-class flagship, Tomed. The invasion was led by Admiral Aventeer Vokar. Tomed descended into the atmosphere in order to shock the Koltaari, who were previously unaware of the existence of extra-terrestrial life.
Later in 2311, following the Tomed Incident, the Romulans retreated within their borders and abandoned the Koltaari system. The Koltaari later began receiving Federation aid. (TLE novel: Serpents Among the Ruins)