Vendikar was the inhabited third planet orbiting the primary Eminiar. This system was located in NGC 321. This was the homeworld of the Vendikans, a pre-warp humanoid species. (TOS: "A Taste of Armageddon")
For over five hundred years, Vendikar was governed by a planetary government. This government was headed by the Vendikar High Council. There was a direct channel between this council and the High Council of Eminiar, which, by 2267, hadn't been used for centuries.
Vendikans were the descendants of colonists from the planet Eminiar VII who settled this world in the distant past. The civilization was technologically advanced, having had space flight for several hundred years, but it had elected not to venture outside of its solar system.
Vendikar had been fighting a war with the principal planet in the system, Eminiar VII, for five hundred years. The conditions of this war were stipulated in a treaty signed by both worlds. This was a simulated war with causalities determined by computer projections, and the people willingly killing themselves in disintegration stations. Legitimate targets in the war included vessels orbiting the planet. The reneging of this treaty by either side could result in a real war.
In 2267, the USS Enterprise visited the planet Eminiar VII. During the visit, when his ship and crew were threatened with destruction, Captain James T. Kirk ended the war abruptly by destroying the computers. Ambassador Robert Fox began work with the two planets to establish a lasting peace. (TOS: "A Taste of Armageddon")