UNSC Tannenberg
From Halopedia, the Halo wiki
The UNSC Tannenberg was a United Nations Space Command Frigate operational in the 2530s.
On January 13, 2531, the Tannenberg was near the Groombridge 34 System where it assisted the Office of Naval Intelligence Prowler UNSC Circumference in attempting to locate Spartan-051, who had gone missing in the area. It was unable to locate him, and was soon after called to action because of Covenant activity nearby.
Presumably, it is named after the battle of Tannenburg, a decisive German victory on the Eastern Front during the First World War.
