Ilesa Ecaz was the second eldest daughter of Archduke Armand Ecaz, and was the intended bride of Duke Leto Atreides I of Caladan. In the twelfth year of the life of Paul Atreides, the Duke finally decided to make commit to a marriage to cement the friendship between House Atreides and House Ecaz, marriage to Armand's daughter, Ilesa. Although the Duke had already announced to the Imperium that Paul was his intended heir, there was still coolness to the idea of marriage from Leto's concubine, Jessica Atreides. When Ilesa arranged to travel Cala City in the days prior to her upcoming nuptials to Leto, Jessica decided for the sake of everyone involved to strike up a friendship with Ilesa.