NIA is the twenty-fourth of the thirty Aethyrs, or Airs, of the Enochian system, the thirty spiritual regions delivered to the mathematician John Dee and the scryer Edward Kelley in 1584, and named in the record Dee compiled from those sessions. Its three-letter name, NIA, was received letter by letter through Kelley's scrying.
Place in the system
Each Aethyr is said to contain three Governors among whom the ninety-one Parts of the Earth are divided.
The thirty Aethyrs are the raw gift of the Dee-Kelley sessions; the elaborate visionary content attached to them in modern practice belongs to a later layer, above all Aleister Crowley's The Vision and the Voice, his record of scrying all thirty Aethyrs in 1900 and 1909. The Aethyr is described here as an element of that documented historical tradition, studied as such, its entities not reified.
The three Governors
NIA's three Parts are Orcanir, ruling Media, under King Zarnaah of the tribe of Manasseh; Chialps, ruling Arriana, the Ariana of the classical geographers covering eastern Iran and parts of Afghanistan, under King Lavavot of the tribe of Gad; and Soageel, ruling Chaldea, under King Zinggen of the tribe of Zebulun. Media is named here and again, as Median, three Aethyrs further on, and Chaldea itself appeared earlier under the spelling Chaldei; since Dee compiled the table from his own session records, these five clear duplications across the ninety-one belong to the material and are not a later copyist's error.