Athos under fire during the Klingon War
Athos was a Federation colony on the moon of J'Gal in the 23rd century.
The colony was located in disputed space between the Federation and the Klingon Empire. During the Klingon War of 2256–57, the Klingons attempted to conquer it and every other colony in the sector. In response, Starfleet established a base near Athos to contest the Klingon advance. The Klingon forces on J'Gal were commanded by General Dak'Rah; he ordered his soldiers to kill everyone aside from Klingon warriors, which led to the mass torture and murder of over a thousand civilians at Athos. The survivors were evacuated by a Starfleet convoy. (SNW: "Under the Cloak of War")