This is paraphrasing from the New Guide To Characters and the theforece.net chronologies: 10 months after the Battle Of Yavin: Thrawn is promoted to Vice-Admiral. Shortly before the Battle Of Hoth: Thrawn receives command of the Nogri from Vader. Shortly after the Battle Of Hoth: Thrawn is officially promoted to Grand Admiral, after stifling Grand Admiral Zaarin's attempted coup. The Zahn short stories and other sources keep Thrawn popping in and out (well, mostly out) of the known Galaxy until the Battle Of Endor, after which he stays put in the Unknown Regions. Until he bitch-slaps the New Republic five years later. I am typing up everything we discussed for this film and will have it with me when I get to the threatre. JediRacer EDIT: Per CR's request.