The ancient humanoids are one of the oldest sentient species and possibly the first humanoid species to evolve in the Milky Way Galaxy. They flourished some 4.5 billion years ago and explored the galaxy, but found no other lifeforms like themselves.
Believing that the life span of a single species was finite, the ancient humanoids seeded the primordial environments of many planets with a DNA code that would direct the evolution of life on that planet towards a form similar to their own. At least Earth, Indri VIII, Loren III, Ruah IV, and Vilmor II were directly seeded by the ancient race. Other species that likely originated from seeded primordial seas included Klingons, Romulans/Vulcans, and Cardassians. Some of the fragments of DNA also contained parts of a computer program designed to display a holographic message from an ancient humanoid explaining her race and their actions. It was hoped that their descendant species would come together in the spirit of cooperation in order to assemble the program.
In the 2360s, the noted Federation archaeologist Professor Richard Galen discovered the existence of the program and began collecting the genetic samples. However, the Klingons and Cardassians also learned of the program and sent expeditions of their own to assemble it, each believing it to contain a great technological advance, while the Romulans observed all of them under cloak. After Galen's death, Captain Jean-Luc Picard of the USS Enterprise-D was able to convince the Klingons and the Cardassians to cooperate with them to finish the program.
The last part of the program was obtained on Vilmor II, and the message was played to the assembled members of each present party. The Klingons and Cardassians rejected the message due to their own prejudices, but the Romulan captain later expressed to Picard in confidence that perhaps their races were not as different as they had previously believed. (TNG: "The Chase")