Treaty of Cheron
The Treaty of Cheron ended the Romulan wars in 2160 and established the Romulan Neutral Zone. Although the treaty was signed by the Romulan Star Empire and Earth's world government, it was upheld after the creation of the United Federation of Planets. The later Treaty of Algeron, signed by the Federation, reaffirmed the Romulan Neutral Zone.
This treaty was signed by the United Earth Government and the Romulan Star Empire in 2160. This treaty brought about the end of the Earth-Romulan War. The Battle of Cheron is generally considered the decisive battle in the Earth-Romulan War. Both sides recognized the major victory achieved here by Earth as a humiliating defeat of the Romulan military. This event would establish long-term political effects within the Romulan Empire lasting well into the 24th century.
Following the Battle of Cheron the two sides negotiated a treaty via subspace radio. Among other things, it established a Neutral Zone, entry into which by either side would constitute an act of war. Earth set up at least eight outpost stations on asteroids along its side of the Neutral Zone to monitor Romulan activity. (The Original Series: "Balance of Terror")
In 2267, the Neutral Zone Treaty was expanded after the First Federation-Klingon War to give additional specified legislation in the Neutral Zone. This included the establishment of a joint Federation-Klingon-Romulan colony on Nimbus III and the outlawing of the use of Vendorians as spies. (Star Trek V: The Final Frontier and The Animated Series: "The Survivor")
- Campbell, Brian, et al. The Price of Freedom: The United Federation of Planets Sourcebook, Culver City, CA: Last Unicorn Games, 1999.