Priests may have generally brought up their sons to the occupation; but other persons, even foreigners (and if foreigners, then _a fortiori_ natives), could be enrolled in the order, and attain its highest privileges.
It was at once a sacerdotal and a learned body.

It had a literature, written in peculiar language, which its members were bound to study.
This language and this literature were probably a legacy from the old times of the first (Turano-Cushite) kingdom, since even in Assyria it is found that the literature was in the main Turanian, down to the very close of the empire.

Astronomy, astrology, and mythology were no doubt the chief subjects which the priests studied; but history, chronology, grammar, law, and natural science most likely occupied some part of their attention.

Conducting everywhere the worship of the gods, they were of course scattered far and wide through the country; but they had certain special seats of learning, corresponding perhaps in some sort to our universities, the most famous of which were Erech or Orchoe (Warka), and Borsippa, the town represented by the modern Birs-i-Nimrud.

They were diligent students, not wanting in ingenuity, and not content merely to hand down the wisdom of their ancestors.