New Defender's Study Bible Notes
6:2 Achmetha. Archaeologists say that the Persian emperors of this period used four capitals—Babylon, Persepolis, Susa, and Achmetha (or Echatana). Accordingly, the “search” (Ezra 6:1) began in Babylon, but the scroll was finally found in the palace at Achmetha. This is the only reference in the Bible to this city.
6:4 great stones. Thus the heavy construction, using large stones and new timber, which Tatnai had questioned (Ezra 5:8), were indeed found to have been specifically authorized by Cyrus.