structural:scholar_edition, structural:summarization
Tax districts

Darius also introduced a regulated and sustainable tax system that was precisely tailored to each satrapy, based on their supposed productivity and their economic potential. For instance, Babylon was assessed for the highest amount and for a startling mixture of commodities – 1,000 silver talents, four months' supply of food for the army. India was clearly already fabled for its gold; Egypt was known for the wealth of its crops; it was to be the granary of the Persian Empire (as later of Rome's) and was required to provide 120,000 measures of grain in addition to 700 talents of silver. This was exclusively a tax levied on subject peoples. There is evidence that conquered and rebellious enemies could be sold into slavery. Alongside its other innovations in administration and taxation, the Achaemenids may have been the first government in the ancient Near East to register private slave sales and tax them using an early form of sales tax.

Other accomplishments of Darius' reign included the codification of the dāta (a universal legal system which would become the basis of later Iranian law), and the construction of a new capital at Persepolis.