Ministry of Tranquility
From Halopedia, the Halo wiki
The Ministry of Tranquility is known for keeping an extensive library of Forerunner glyphs. The Minister Prophets employ Engineers for use as librarians. They also pay Jackal captains commissions for their work.[1] Their main function seems to be the acquisition and deciphering of Forerunner artifacts.
The Ministry of Tranquility commissions a large and sizable Fleet of missionary ships, such as the Minor Transgression, to search the outer edges of Covenant territory for relics of the Forerunners. It is the only Ministry that the Grunts work for. They attach Deacons to appropriate Jackal missionary ships to ensure that the piratical creatures obey Ministry laws and regulations, a task at which they rarely succeed.[2]
Notably, the Prophet of Regret was formerly the Vice Minister of Tranquility before ascending to the position of Hierarch.