The Logrus of Thelbane was most commonly manifested within a labyrinth deep beneath the palace of Thelbane in the capital city of that Realm. However, there was another manifestation of it in the small town of Sarrabann - within the summer palace of King Swayville that was located there.
During the civil wars in Thelbane after the passing of Swayville, the summer palace became a focus for some of the resistance to the rule of Mandor, particularly as Swayville's daughter and grand daughter made their stand there. Swayvanilla, the grand daughter found for herself a champion, and under the rule of her and her husband Dalt (a renegade son of King Oberon of Amber), the Realm of Sarrabann was founded.
The early days were not easy - most of the old Houses of Chaos stuck with the staus quo and backed Mandor, though with the loss of a major portion of House Hendrake, who were the source of most of the armies of Thelbane, in an unexplained volcanic erruption at their training grounds, Mandor never had the necessary forces to march into Sarrabann and finish them off.
Time passed, and it seemed that Sarrabann might fail simply though ecconomic attrition. However, their fortunes were greatly improved when the nobles of House Helgram made the unilateral decision to quit Thelbane and move to Sarrabann, effectively announcing that House Helgram was underwriting Sarrabann.
This move did not come without a price though - the queen mother of Sarrabann, Swayvanna, had been seeking her own alliance with Randol Yorke, the President of the Federation of American States (in the Inside). The price of survival for Dalt and Swayvanilla was the exile of the royal mother, and the end of their support for the Federation.
Sarrabann now prospers, still ruled by Dalt and Swayvanilla, backed by the House Helgram, and also by Princess Dara, who clearly has hopes that Sarrabann will support her in her quest to have Mandor declared a regicide, for the deposing of her son.