A governmental organization of the kingdom of New Equestria, charged with the oversight of magic use in the kingdom and with specialized magical law enforcement and investigation. Its director reports to the New Equestrian cabinet Minister of Magic, conventionally in recent centuries the same person as the royal court mage. (The positions were originally independent, with the royal court mage having de facto life tenure. The minister of magic is generally replaced whenever a new government is formed.)
The Bureau dates from the reign of Queen Ephemeris, and essentially supplanted the pre-catastrophic position of Ensconced Archmage of the Isle of Yore, which went extinct with the death of Bluestar the Brilliant.