The Battle of the Great Bear was a naval battle between a UNSC fleet of seventeen warships and three Covenant warships in the Groombridge-1830 system. The UNSC fleet was led by the UNSC Everest and Admiral Preston Cole. The battle resulted in eleven UNSC ships and two Covenant ships being destroyed. The third Covenant ship ultimately crash-landed on the surface of the planet, resulting in the capture of a Sangheili prisoner.
These events are referenced in the short story The Impossible Life and Possible Death of Preston J. Cole, in the anthology Halo: Evolutions, which was the subject of a Halo Book Club on January 3rd, 2018, and the comic Halo Wars: Genesis which was the subject of a Halo Book Club on February 9th, 2017.