The UNSC Pillar of Autumn, (hull classification symbol C-709), was a Halcyon-class light cruiser in the UNSC Navy. It was informally referred to as the Autumn, and, in some cases, the Pillar. Prior to the Fall of Reach the Pillar of Autumn was selected to support Operation: RED FLAG, a SPARTAN-II mission to capture Covenant leaders. Captain Jacob Keyes was placed in command. The operation was forestalled by the Covenant assault on Reach; the cruiser carried some of the few UNSC survivors and fled the system having lost most of its intended SPARTAN-II passengers.