Over a thousand years ago, the planet was divided in numerous highly-industrialized city-states who constantly warred with each other and destroyed great parts of the planetary ecology. Then, the planet's leaders came to reason and began pacifying the planet and cleaning the environment, using the newly-created story of Ardra to justify themselves to their people and draft a constitution. The planet isolated itself from the rest of the galaxy, until it was again confronted with off-world influence when it was first contacted by a Klingon expedition in 2297. Sometime after this, a Federation research station was established on the planet. In 2367, this station was headed by Doctor Howard Clark.
In 2367, the planet fell into chaos when, according to the Ardra story, a fabulous thousand-year period of peace and wealth would come to an end and the planet would be turned over to Ardra. A con artist used this myth and modern technology to present herself as Ardra and to bring the planet under control, but her true identity was successfully revealed by the crew of the USS Enterprise-D.
There was, according to Data, an obscure precedent in Ventaxian law. The case involved a contract dispute over services rendered by a Klingon craftsman on the construction of a Ventaxian home. As the case was between an alien claimant and a Ventaxian, both sides decided that arbitration rather than courts should decide the case. Both sides chose an arbiter. This was the only known case involving an alien claimant. (TNG: "Devil's Due")