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 by, attaching 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]
It should be noted that the former Vice Minister of Tranquility would later become the High Prophet of Regret.