Vordarian's Pretendership (vohr-DAIR-ee-uhn) was a major event in recent Barrayaran history, recounted in the novel Barrayar, taking place during the first year of Aral Vorkosigan's Regency and ending shortly before the birth of Miles Vorkosigan.
Emperor Ezar had just died; his son Crown Prince Serg had died earlier in the Escobar War, leaving only Ezar's grandson Gregor Vorbarra alive. Thus four-year-old Gregor became Emperor; for his minority, Ezar had appointed Admiral Lord Aral Vorkosigan to be Gregor's guardian and Regent.
Vordarian The Pretender
The recent succession to the throne of Barrayar had been irregular, and Count Vidal Vordarian was among those with a rival claim. After Ezar's death, Vordarian amassed support and forces and staged a coup in the capital. Imperial Security had learned of the plot, and was preparing to arrest Vordarian, but he learned of their plans, and kicked off his coup a month ahead of his original schedule.
Vordarian invaded the Imperial Residence and managed to capture Princess Kareen, Gregor's mother. Although mortally wounded, ImpSec chief Captain Negri got Gregor out of the capital and took him to Vorkosigan Surleau, the Vorkosigan summer home where the Lord Regent was recuperating from an earlier assassination attempt that had been orchestrated by Vordarian.
Eventually, Vordarian declared himself Prime Minister and Regent for Kareen, and then later Emperor. Claiming that Vorkosigan had killed Gregor in an effort to usurp the Imperium, Vordarian worked to appeal to the people that he was their rightful Emperor.
Because her unborn son, Miles Vorkosigan, was still in a captured uterine replicator in Vordarian's control, Cordelia launched an unsanctioned mission to retrieve him. She successfully rescued Miles, his cousin Ivan Vorpatril, and Alys Vorpatril; however, during the rescue, Princess Kareen was killed by nerve disruptor and one wing of the Imperial Residence burned to the ground. Vordarian was then decapitated by Sergeant Bothari, using Lt. Koudelka's swordstick, on Cordelia's orders; his head was brought covertly back to Tanery Base and shown to the loyalists as well as several of Vordarian's officers who were present for negotiations.
Vordarian's Pretendership was the first major test of the Vorkosigan Regency, and while it would not be the last, Aral completed his time as Regent and turned power over to Gregor, who became an effective ruling Emperor. Miles Vorkosigan survived, and embarked on a successful career. Cordelia's reputation was rather firmly established among the Vor due to her "shopping trip" to the capital, a reputation she thought overblown, but still useful.