Upon her arrival in Camaar, Polgara claimed to be the Duchess of Erat and acted the part. Captain, later General, Brendig informed her that his uncle was the Earl of Erat. He later informed her that she was the duchess and had a large account being held by the King of Sendaria.
Erat seems to have two usages: as a duchy, it is the region of Sendaria and as a town, is the capital of the duchy of Erat. Brendig's uncle is the Earl of the town and Polgara the Sorceress is the Duchess of the region of Sendaria. The duchess of Erat is "the most important person in Sendaria" (Polgara the Sorceress).