Tattenai (or Tatnai or Sisinnes) was a Biblical character and a Persian governor of the province west of the Euphrates River during the time of Zerubbabel and the reign of Darius I. He is best known for questioning King Darius in regard to the rebuilding of a temple for the Lord, God of Israel. He was generally friendly to the Jews. The rebuilding was being led by Jeshua, son of Jozadak, and Zerubbabel, son of Shealtiel, and had been issued by King Cyrus I. Tattenai wrote a letter to King Darius to ask of these statements were true, and then King Darius wrote a letter confirming that the statements were true. In the letter, Darius asked that the people do everything they can to support this rebuilding financially, and that they do nothing to impede it lest they suffer harsh punishment.