The Tau Cygna system was a star system. The fifth planet of this system, Tau Cygna V, was suitable for colonization. This system was located in the de Laure belt. According to the provisions of the Treaty of Armens, the Sheliak Corporate could exercise a claim for this system.
In the mid-23rd century, the colony ship SS Artemis landed on Tau Cygna V. The survivors built a colony which lasted for nearly a century. However, under pressure from the Sheliak Corporate, the colonists were relocated to a new home. (TNG: "The Ensigns of Command")