Pledge of Holiness

The Pledge of Holiness was a Covenant Carrier of an unknown class that participated in the Rending, where the Ussan rebel Sangheili made a final stand on the Forerunner Shield World that they called the Refuge in 850 BC. It was captained by Commander Trok 'Tanghil and was the flagship of Mken 'Scre'ah'ben(aka the Prophet of Inner Conviction), who was the leader of the fleet sent to the Refuge. While it did survive the battle unscathed, it is unknown what happened to the ship after the battle.

Sources:

 * 1) Halo: Broken Circle