The Athosians were moved there after some of the Lanteans from the Tria returned to reclaim Atlantis. However, after the return of the Atlantis expedition, the Athosians chose to stay on the planet, now named New Athos, rather than move back to Lantea. They had managed to make a permanent settlement there. However, a year later the Wraith Michael Kenmore sent an army of his Hybrids to attack and kidnap the Athosians. The army of at least 50 men attacked during the middle of the night, and kidnapped all the Athosians there. However, the planet was then overrun with Bola Kai.
The next day, Teyla Emmagan and Dr. Jennifer Keller came to meet the Athosians. They noticed that the settlement was deserted and discovered the Bola Kai. The following day, the First Atlantis Reconnaissance Team managed to drive the Bola Kai from the planet. The Expedition later sent a forensics team to learn about what happened to the Athosians. However, about six months later, the Athosians were found and rescued on another planet, and moved back to New Athos. (SGA: "The Return, Part 1", "Missing", "The Seer", "The Kindred, Part 2", "Legacy: Homecoming")
Guide eventually reveals that he had his alliance declare New Athos off-limits to the Wraith. Guide explains that he didn't want to get into a dispute with the Tau'ri over the territory and the Athosians had been so badly culled, they weren't worth a fight. However, after the fall of Todd's alliance and the rise of Queen Death, this protection disappears. (SGA: "The Lost")