Alisander Gyrn was a member of an ancient trading family from Sirius what entered ComStar. He fall prey to delusions years before that led him to believe he was the reincarnation of Jerome Blake. Under the thrall of these delusions, Gyrn had spent years recruiting devoted followers in both the Procyon and Sirius systems, and he seized on the disruption caused by Operation GUERRERO to lead his followers in an uprising. Gyrn seized the HPG stations in both systems, and used assassins to kill key officers in Jo's Fourth Cavalry and Boodelay's Backup, the mercenary forces employed by the two planetary governments. Followers of Gyrn who had infiltrated the support staffs of both mercenary units were responsible for sabotaging key equipment, such as the mercenary commands' JumpShips, and Gyrn had the supplies to both units cut off. Many of the mercenaries attempted to contest Gyrn's actions, but were unsuccessful when they tried to depose Gyrn, and the survivors were forced to retreat into the wilderness.
With the HPGs under his control and the local mercenary forces neutralized, Gyrn's rule over the newly-formed Sirian Holds was announced by his loyal followers to the stunned populations of both systems. No mention was made of the alleged divinity of Alisendar Gyrn; instead, the takeover was pitched as freeing the systems from the Great Houses, and there was relatively little protest from the population, at least at first. When word reached the wider population of what had happened to the mercenary troops, along with the discovery that Gyrn was in control of the HPG systems, protests broke out. As the protests accelerated towards becoming an open revolt, Gyrn announced that both systems needed to be "purified"; this purification consisted of destroying all modern technology. Gyrn's followers rounded up intellectuals, technicians, dissenters and various other groups, with the roundups being described as the beginning of a process of re-education; instead, those gathered up were murdered in killing fields outside the capital city, to prevent them posing any kind of threat to Gyrn.
When news began to spread of atrocities being committed in the Sirian Holds, it provoked a response from General Helen Thrall, the Commanding Officer of the Sirian Lancers brigade. Thrall had been agitating for years in an attempt to persuade the Captain-General of the Free Worlds League that the four systems that had once made up the League province known as the Sirian Concordance should be recaptured from the Federated Commonwealth. Two of the four systems - Graham IV and Pollux - had been recaptured during Operation GUERRERO, but the League had stopped short of recapturing Sirius and Procyon. The news of Gyrn's actions in the Sirian Holds convinced Thrall that she could no longer wait, and she issued a brief message to the LCCC announcing that she would be taking the Lancers to liberate both systems, with or without support from the Free Worlds League Military. Captain-General Thomas Marik responded by deploying the Fourth Free Worlds Legionnaires to accompany the three regiments of Lancers. Thrall's task force recaptured both systems in September 3058, but learned that Gyrn had killed tens of thousands of people.
- Chaos March, p. 91, "Sirian Holds"
- Field Manual: Free Worlds League, p. 84
- Shattered Sphere, p. 82, "General Helen Thrall"