Despite the fact that his concubine was from a noble (but exiled) family, Duke Leto Atreides decided not to marry Kailea Vernius due to his concept of a Duke's duties to both his people and his House. It was then when Archduke Armand Ecaz, a friend of House Atreides, offered his eldest daughter and heiress, Sanya, in marriage to the Atreides Duke.
However, during the beginning of the new conflict between House Ecaz and House Moritani, Sanya was kidnapped by Moritani agents and, on orders of Viscount Hundro Moritani, her father's enemy, she was publicly executed along with her uncle (Armand's brother). Leto felt sorrow for Sanya's death, whom he considered an attractive woman.
Years later, in the War of Assassins of 10,187 AG Sanya's younger sister, Ilesa, last heiress of House Ecaz, replaced her role as bride to Leto Atreides, but was also killed during an assassination attempt during her wedding on Castle Caladan.
With the deaths of both Sanya and Ilesa, as well as their uncle, House Ecaz lose all their heirs, leaving Archduke Armand as the last member of his family.