The people of Nasya were originally brought to their planet from Earth by an unknown Goa'uld sometime before 1700, eking out a life on their new world. For reasons unknown, the Goa'uld left the planet around 1700 and the people started to live their life free of false gods, most of them living in a small village near the Stargate which was on the border of a generous source of water.
Their peace would not last forever, however, as the Tok'ra Jolinar of Malkshur fled to the planet by spaceship in an attempt to hide from the Goa'uld. There, Jolinar's symbiote took a new host in the body of a Nasyan male named Quinta in order to hide itself among the local populace while Rosha—Jolinar's previous host—left the planet by Stargate. Edrekh, an Ashrak sent by Cronus, chased Jolinar to Nasya but was thrown by Jolinar's ploy and, rather than searching the local populace for her new host, instead chased Rosha to another planet.
Jolinar herself chose to remain hidden among the populace, hiding herself from even her own host and allowing him to live his life as he did before. This plan, though well thought out, did not last forever as Edrekh retraced his steps to Nasya after discovering that Rosha no longer held Jolinar's symbiote. Cronus, having grown impatient, attacked the planet through force in the hopes of drawing Jolinar out of the populace. This plan may have worked if not for the timely arrival of SG-1, who started to evacuate the Nasyans to Earth. Jolinar's host, among these evacuees, was struck down before he could make it to the Stargate but Jolinar herself survived, transferring into Captain Samantha Carter, a member of the Tau'ri and SG-1 when she tried to help the dying man.
The Tau'ri managed to evacuate 237 of the Nasyans to Earth, unwittingly taking both Jolinar and Edrekh along with them, despite Cronus's attack by Death Gliders. Cronus himself chose to then occupy the planet after this, ordering his Jaffa to overrun the planet. This was discovered by Stargate Command when they attempted to send a MALP through the Stargate. Rather than send the Nasyans back to slavery, the Tau'ri instead relocated them to the world of Gemmond where they integrated with the population and built new lives for themselves. (RPG: "Friends and Foes: Stargate Season Two") (SG1: "In the Line of Duty")