In Greek mythology, Cronus was one of twelve Titans, immortal beings of great strength and power, who ruled before being overthrown by the Olympians. The twelve children of the Titans, led by Cronus's son Zeus, engaged in a ten-year war that elevated them at its conclusion to the principal deities of the Greek pantheon.
Cronus, allying with the Supreme System Lord Ra and with Apophis—one of his mortal enemies—were among the main System Lords who allied to overthrow Sokar, with Cronus being the one to formally banish him. Following the death of Ra, Cronus was, alongside Apophis and Heru'ur one of the Goa'uld who largely came to fill the void left by Ra's demise.
Ronac, the father of Teal'c, was his First Prime, but had ordered a retreat, for which Cronus killed him, crushing his prim'ta, causing a slow, agonizing death. Teal'c and his mother were banished to Chulak, where Teal'c vowed to become First Prime of Apophis so that he would be in a position to someday avenge his father. Cronus is described by Teal'c as being the most influential of the System Lords. (SG1: "Fair Game", "Crossroads")
Cronus was also a bitter enemy of the Tok'ra. Upon learning that the Tok'ra Jolinar of Malkshur was on Nasya, he dispatched the Ashrak Edrekh to kill her. Apparently tired of waiting for Edrekh to act, he sent a Death Glider squadron down to attack the Nasyans, but they were evacuated by SG-1. The symbiote Anker, who replaced the Tok'ra Cordesh to act as a spy within the Tok'ra, later sent word to Cronus of the contact of the Tau'ri and the Tok'ra. Cronus sent two motherships to deal with them, but the Tok'ra were given advance warning, and Colonel Jack O'Neill discovered Anker's duplicity. Thus, Cronus bore indirect responsibility for the formation of the Tau'ri-Tok'ra alliance. (SG1: "In the Line of Duty", "The Tok'ra, Part 1", "The Tok'ra, Part 2")
It was assumed that because Cronus was highly influential among the System Lords, and a rival of Apophis, that he might have used his pull to convince the other System Lords to not join Apophis in his attack on Earth in 1998. (SG1: "Fair Game")
When the Asgard sought to have Earth included in the Protected Planets Treaty, Cronus led the delegation, which included Yu and Nirrti. The System Lords agreed to allow Earth into the treaty, in return for surrendering both the Alpha and Beta Stargates. Nirrti opposed the plan, and used a cloaking device to conceal herself to attack Cronus, framing Teal'c. Nirrti then falsely tried to heal him, but Major Samantha Carter healed Cronus herself after her duplicity was exposed. In return, Cronus agreed to support the treaty, and allow Earth to retain its Stargates, but warned the Tau'ri that any who were captured would be dealt with harshly. Nirrti was then taken into his custody. (SG1: "Fair Game")
Two years later, Cronus took the planet Juna, previously controlled by Heru'ur. When the robotic copies of SG-1 came through, he had the Daniel Jackson double executed. His surprise at their robotic appearance caused a weakness of his position among the People of Juna, who reasoned that a true God would have known about their true natures.
When they learned that they had gone to Juna, the real SG-1 came to rescue them, and Cronus was confronted by both the robotic Teal'c and the real Teal'c. Cronus attempted to kill the real Teal'c by killing his prim'ta, like he had killed his father, but the robotic Teal'c shot Cronus three times with a Staff weapon in the back, killing him. His body was then showed to the people of Juna to prove once and for all that the Goa'uld were not gods.
SG-1 received the added bonus of gaining control of Cronus' Ha'tak, which was used to destroy Apophis' fleet. Apophis eventually died when Cronus' Ha'tak was crashed into Delmak by SG-1 and Jacob Carter. (SG1: "Double Jeopardy", "Exodus", "Enemies")
The death of Cronus, followed by the death of Apophis a few days later, caused the System Lords to enter into a war that the Tok'ra hoped would last for years. However, an adverse effect was that it allowed Nirrti to escape and resume her activities in searching for a hok'tar, eventually bringing her back into contact with both the SGC and SG-1. Worse, it merely accelerated the events that resulted in the return of Anubis. (SG1: "Enemies", "Rite of Passage", "Summit", "Last Stand")
- Cronus, like other System Lords, was in the service of Ba'al during an alternate timeline. He conspired with Ba'al's queen, Qetesh, to overthrow Ba'al, a plot which half-succeeded. Though Ba'al was killed and he and Qetesh took over, Qetesh was killed by SG-1. Though it is assumed Earth would have been destroyed and he would have taken control of the System Lords, it is unknown what his fate was, as history was restored. (SG1: "Continuum")
In the Goa'uld mothership captured by SG1, the throne of Cronus sits in the mothership's main bridge. Its inscription reads, in Greek:
ΑΝΤΙOΧΟΙ ΙΕΡΑΣ ΤΥΡΙΩΝ ΔΕΥΣ · ΧΡΩΝΩΣ · ΗΩΣΤΡΥΜ ΔΙΦΣ ΙΛΕΩΣ ΒΑΣΙΛΕΙ ΧΡΩΝΩΣ ΔΙΩ
The words do not form a coherent unity in Ancient Greek, and it seems they are mainly just put together for artistic impression. For example, the Greek name of Cronus should be ΚΡΟΝΟΣ, not ΧΡΩΝΩΣ, as in the text.
Apophis showed great contempt for the throne. He even went as far to call it a," disgusting decoration."