The Byrsa were a primitive, pre-industrial race of Humans who hailed from the planet Cartago, plagued by frequent attacks from Goa'uld seeking new hosts for their young. They were brought to Cartago by the Goa'uld many thousands of years ago, though who this Goa'uld was is unknown. The Byrsa justice system followed the Cor-ai, a trial in which the one who has been injured or wronged determines the proper punishment for the transgressor.
Normally, the Byrsa were a very pleasant society and were artful in the use of fire. They were developed in the culinary arts and the building of relatively tall stone structures, including sturdy holding areas for captured prisoners.
When the chevrons on the Stargate shone red, the Byrsa were alerted that the Goa'uld were on the way. They had caves and tunnels in all directions so they could immediately go into hiding. Unfortunately, the Byrsa were only as fast as the slowest among them as they refused to ever leave anyone behind. Teal'c while in the service of Apophis was aware of this; after being ordered to kill one of the Byrsa to stir their submission Teal'c chose to execute a crippled old man who he believed would slow them down the most. He hoped that by doing so the Byrsa might evade his battalion during their next encounter.
After the son of the victim agreed not to put Teal'c to death for this horrible act (Teal'c had recently proven his worth to the people by fighting for them against a Jaffa battalion), SG-1 agreed to help them fortify themselves against the Goa'uld. (SG1: "Cor-ai")