There are three references to rulers named Darius in the Bible. The first, chronologically, occurs in the book of Daniel, where the ruler is called Darius the Mede (Daniel 6:1). This Darius ruled for two years (538–536 BC) and is best known as the ruler who promoted Daniel to a high position in the kingdom and then cast him into the lions’ den, much against his better judgment. When he saw that Daniel was unhurt by the lions, Darius decreed that “people must fear and reverence the God of Daniel. For he is the living God and he endures forever; his kingdom will not be destroyed, his dominion will never end” (Daniel 6:1–28). It is possible that Daniel used the word Darius (which means “lord”) as a title for the ruler in Babylon, rather than a proper name. Daniel 6:28 refers to “the reign of Darius and the reign of Cyrus the Persian,” showing that Darius and Cyrus ruled concurrently. This has caused Bible scholars to posit that Darius was appointed viceroy over Babylon by his nephew, King Cyrus.
The book of Ezra mentions another king named Darius, also known as Darius I or Darius the Great. This was the son of Hystaspes, a king of Parsa. Darius I ruled Persia from about 521 to 486 BC. Darius I is presented in Ezra as a good king who helped the Israelites in several ways. Prior to Darius’s reign, the Jews who had returned from the Babylonian Captivity had begun rebuilding the temple in Jerusalem. At that time, Israel’s enemies did everything in their power to disrupt the construction, and they had succeeded in halting the building during the reigns of the kings Ahasuerus and Artaxerxes (Ezra 4:1–24).
There is some debate about the identity of the “Ahasuerus” or “Xerxes” mentioned in Ezra 4:6 as ruling before Darius I. It is likely that this king is also known in history as Cambyses II, a son of Cyrus the Great. The “Artaxerxes” in Ezra 4:7 is called, in other historical records, “Smerdis” or “Bardiya,” another son of Cyrus. That king ruled only seven or eight months. Ezra spoke of Cambyses using his Chaldee name (Ahasuems) in Ezra 4:6, and by his Persian name or title (Artaxerxes) in verse 7. In that case, Ahasuerus and Artaxerxes refer to the same person — the king who immediately preceded Darius.
When Darius became king, construction of the temple resumed in the second year of his reign. But the Jews’ enemies again attempted to thwart their efforts. Tattenai, the Persian governor of Judea, wrote a letter to Darius in an effort to turn the king against the Israelites and stop the building of the temple. But Darius responded by commanding Tattenai and his companions to stay far away from the site and let the Jewish elders continue with the rebuilding. Furthermore, the king decreed that the Jewish workers were to be paid from the royal treasury, that the builders would be given whatever was needed for the burnt offerings, and that anyone attempting to destroy the temple or disobey his decree would be impaled on a beam from his own house, which would be made a pile of rubble (Ezra 6:1–12). By his decrees, Darius I showed himself to be a friend of Israel, and the Jews in Jerusalem prospered under his watch. The temple was completed in the sixth year of his reign (Ezra 6:15).
A third reference to a ruler named Darius occurs in Nehemiah 12:12, which refers to the “reign of Darius the Persian.” It is unclear exactly who this Darius is, but most historians believe it to be Darius Codomannus (336–331 BC), the last king of the Persian monarchy who was defeated by Alexander the Great.