UNSC Allegiance
From Halopedia, the Halo wiki
The UNSC Allegiance is a frigate in the UNSC. In 2552, it responded to the signal sent by Commander Keyes of the Iroquois. It intercepted a retreating Covenant carrier.
Note: This vessel is called the "Alliance" on page 145 of Halo: The Fall of Reach and then called the "Allegiance" on page 154. This is likely an error on the part of the author. Most fan sites, however, like to assume that the Allegiance and the Alliance are two separate ships. See: List of Inconsistencies in Halo.
