Ra appointed a new hierarchy of rulers to aid in the governing of the Goa'uld. By once again dividing the spoils of several millennia of conquest, Ra created a cadre of System Lords. Membership to the body was by vote of the existing members and afforded many benefits, including access to Unas hosts in order to maintain armies. In this act, Ra created the power structure that served the Goa'uld through to present day, and anointed Egeria as his Queen. Ra also took other queens, such as Hathor, during his long rule.
Naquadah, the foundation of both Ancients and Goa'uld technology was discovered in small quantities. Ra petitioned the System Lords for a new era of expansion and offered exclusive rights and access to Unas in exchange for Naquadah shipments. Their attention diverted, the System Lords began a race of exploration. (SG1: "Living Gods: Stargate System Lords")
13,000 to 3,000 B.C.
The Asgard, a species and one-time ally of the Ancients, declare themselves enemies of the Goa'uld System Lords. The Goa'uld relish the opportunity to once again flex their muscles, but it soon becomes apparent that the Asgard are more than a match, leaving the System Lords to retreat and lick their wounds.
Their resources running low, the System Lords launch a daring attack against the Asgard and Furlings – two longstanding allies. The Goa'uld strike with surprise and land a crushing blow, but in the years that follow, their enemies fight back with vengeance. The Asgard deal the parasites several major setbacks but do not press the attack, not fully realizing the danger that the Goa'uld pose to their galaxy and others.
Ra, badly injured, flees Asgard pursuers into an alien system. There he finds a lush world inhabited by a large population of primitives that bow to his divinity. The world – Earth – contains a vast number of natives that are suitable for blending. Transferring his symbiote into an Egyptian boy, Ra is infused with new vigor and life. Ra quickly determines that humans provide a near ideal host for the Goa'uld. Using a Stargate brought with him, Ra claims the world of the Tau'ri as his own.
Ra institutes a ritual of stewardship, allowing each System Lord to visit the Tau'ri world and claim followers, who are then taken to a world of the Goa'uld choice and used as breeding stock. In order to maximize the number of potential slaves, the power of the Goa'uld overlords are expanded, placing them in charge of the entire breeding worlds, such as Chulak.
Ra divides the Earth by strict geographical lines, ensuring that no Lord encroaches upon another territory. A significant number of Goa'uld rise to power during this time and are chronicled in the mythology and history of the Tau'ri.
The Goa'uld use the Tau'ri as a template to create the ultimate host, the Jaffa, who serve as incubators for Goa'uld larva. A larval parasite serves as a Jaffa's immune system. Without a larval symbiote, however, no Jaffa can survive for more than a few hours, effectively enslaving the Jaffa.
Setesh, Osiris and Isis unsuccessfully attempt to assassinate Ra. Ra strips them of their status as System Lords and condemns them to an eternity of suffering. Both Osiris and Isis are forcibly removed from their hosts and placed in canopic jars. However, Setesh goes into hiding.
The Tau'ri learn the truth of there would be rulers. In a moment when the System Lords are at their most complacent, they overthrow their Jaffa warriors, killing several Goa'uld, and bury the Stargate. While the loss of the Tau'ri is a great affront to Ra, the continuing battle with the Asgard demands his attention again. With numerous breeding worlds throughout known space available to them, the Goa'uld are unconcerned with the Tau'ri and resolve to deal with the problem when it is convenient to do so. As time goes on however, the Tau'ri are slowly forgotten. (SG1: "Living Gods: Stargate System Lords")
The Queen Egeria spawns the Tok'ra, a group of symbiotes opposed to the ways of the System Lords. Ra captures her, and sentences her to "eternal damnation" in a stasis jar. (SG1: "Crossroads", "Cure")