World once settled by a band of Free Jaffa following the defeat of the Goa'uld. One particular settler, Tass'an, bore witness to the arrival of an Ori Prior who demanded the worship of the Jaffa to his masters.
When the Jaffa chose to resist, a subsequent visit by the Prior heralded the destruction of the settlement and hundreds of its people. The Prior dialed the Stargate, planted his staff into the ground, and leveled their city.
Tass'an, and perhaps others, managed to escape the deadly attack.
Babylon - Tass'an of the Free Jaffa settlement on Sartorus manages to avoid the destruction of his people to spread the deadly word of the Ori.