In stardate 2/1705, a squadron of Romulan vessels on an exploration and trading mission were exploring the region of space known as the Outback and went around the Romulan Neutral Zone, and visited the the world of Ectair in the Mozinphar's Star system. The Starfleet light cruiser USS Ardent had also stopped at Ectair to pick up supplies. Presuming their presence to be a violation of their peace treaties, the hot-headed Starfleet captain challenged the Romulans and nearly triggered a major diplomatic incident. The Master of Ectair, the former Orion pirate Emerak Mozinphar, intervened in the dispute and mediated in the ensuring discussions.
That the Romulans could simply go around the Neutral Zone posed a serious threat to Federation policy against them, prompting negotiations between the two powers on Ectair itself. These concluded in the signing of the Treaty of Ectair on stardate 2/1810.21, between representatives of the Federation, the Romulan Empire and Ectairian leaders.
The treaty clarified that Romulans could move outside the borders of the Star Empire (legalizing their earlier activites), provided that they did not cross the Romulan Neutral Zone or approach within five light-years of any inhabited Federation planet or defensive outpost. Breaking these strictures was a treaty violation and grounds for hostilities. Romulan vessels were also allowed free access to non-Federation worlds along the frontier. Specifically, it also allowed Federation vessels to trade and take shore-leave at Ectair, and had both the UFP and the Romulan Star Empire agree to respect the neutrality and independence of Ectair.
Many considered the Treaty to a major diplomatic victory for the Romulans, as it returned many freedoms lost during the Earth-Romulan War. Ectair was also profited by the guarantee of their independence and the trade it could receive from both sides. The Federation responded by consolidating its presence, annexing additional space and strengthening its borders. But even after it engulfed Ectair over stardates 2/20 – 2/22, Romulans could freely visit that world. (FASA RPG modules: A Doomsday Like Any Other, Star Trek IV Sourcebook Update)