Achaemenid royal inscriptions
The Achaemenid royal inscriptions are the surviving inscriptions in cuneiform script from the Achaemenid Empire, dating from the 6th to 4th century BCE (reigns of Cyrus II to Artaxerxes III). These inscriptions are primary sources for the history of the empire, along with archaeological evidence and the administrative archives of Persepolis.
Source: Wikipedia — Achaemenid royal inscriptions (CC BY-SA 4.0)