UNSC Agincourt (Ghosts of Onyx)

The UNSC Agincourt was a UNSC vessel, possibly a transport type or a Frigate in operation in the early 2550's. In October 2552, it was sent to planet Onyx to offload supplies at Camp Currahee for the incoming candidates for the new Spartan-III's, Delta Company. As they were leaving, the Camp Commander, Lieutenant Commander Ambrose (aka Spartan-051) asked for observational assistance from the craft after hearing strange sounds coming from Zone 67. The Agincourt discovered, and was destroyed by, two hundred Onyx Sentinels that had been activated within Onyx, the next phase in the Forerunners' plan to wipe out the Flood while still protecting a significant portion of the galaxy's species. There were trillions of them, and they actually formed the planet's crust which explained the absence of tectonic activity.

Background
The Battle of Agincourt was an significant battle in the Hundred Years war involving the Kingdom of England against the Kingdom of France.