Despite their differences, both physically and mentally as well as linguistically, the Valakians and the Menk coexisted peacefully. The Valakians provided land, food and, in some cases, employment for the Menk.
During the 22nd century, a genetic mutation inherent to Valakian physiology resulted in a planet-wide epidemic and the death of some twelve million people. While some strides had been made in combating the illness, a cure evaded Valakian medical science, causing them to seek help from other worlds. Launching numerous pre-warp spacecraft, the Valakians attempted to enlist the aid of more advanced alien species. They were, at some point prior to 2150, visited by the Ferengi and the M'klexa.
As of 2151, Valakis was still a pre-warp world, but had many ships and satellites in orbit. That year, the planet was visited by the starship Enterprise NX-01, after that ship responded to a Valakian ship in distress. Returning ailing Valakian astronauts to their planet, the crew of Enterprise assisted in the search for a cure, until Denobulan Dr. Phlox uncovered evidence indicating that the illness was a step in an evolutionary process that would result in the extinction of the Valakians and the rise of the Menk. (ENT: "Dear Doctor")
Background information Edit
In the final draft script of "Dear Doctor", Valakis, as seen from space, was referred to as "Earth-like." The planet was scripted to appear in a scene set in Captain Archer's ready room, visible outside his window, but Valakis doesn't appear in the final version of that scene. The visual effect representing Valakis from space was evidently a reuse of an orbital view of Qo'noS from "Broken Bow".
The depiction of a Valakian city was scripted to be a "Matte shot of an alien metropolis, sleek and modern." The visual of the city was a digital matte painting created by Black Pool Studios.  The same shot was later reused to represent a futuristic city on Earth in the timestream in "Storm Front".
A scene description of a night view of the Menk village on the surface of Valakis stated, "A cluster of primitive wooden structures are built close together on various levels along a hillside. The lights of the modern Valakian city shine in the distance [....] The village is serene, lit by the glow of torches and cooking fires."
- According to the reference book Star Trek: Star Charts:
- Page 53: Valakis was identified as the sixth planet in the Valakis system. An alternate name, "Menk", might have indicated a shift in power by the late 24th century. The book also described the planet as a Class M member of the United Federation of Planets, admitted in 2236, following their achievement of warp drive that same year. It went on to list the population of Menk as 2.8 billion, and Valakians as 730,000. The official name for the government was the Commonwealth of Menk and Valakis, and the planet had no capital.
- Page 60: Valakis was located in the Beta Quadrant. Sometime between September 15 and October 1, 2151, Enterprise visited this planet.