After Darth Vader, the Sith Lord, killed Archduke Poggle the Lesser on the planet Mustafar in 19 BBY, which is located in the Outer Rim, the Stalgasin hive queen appointed a new archduke by 18 BBY. This new Geonosian leader was responsible for overseeing the soldiers and worker drones of their homeworld, Geonosis, and served as their public figurehead.
However, in 18 BBY, Lieutenant Commander Orson Callan Krennic of the Galactic Empire told Admiral Wilhuff Tarkin aboard Tarkin's Imperial-class Star Destroyer that naming a new archduke was merely a symbolic act. The Empire had essentially taken complete control over the entire species of Geonosians, exploiting them as laborers to construct the DS-1 Death Star Mobile Battle Station.
James Luceno mentioned the archduke in his 2016 novel, Catalyst: A Rogue One Novel.