In the reign of Ahasuerus, in the beginning of his reign, they wrote an accusation against the inhabitants of Judah and Jerusalem.
Ezra 4:6
Surrounding context
4:5 and hired counselors against them to frustrate their purpose all the days of Cyrus king of Persia, even until the reign of Darius king of Persia.
4:6 In the reign of Ahasuerus, in the beginning of his reign, they wrote an accusation against the inhabitants of Judah and Jerusalem.
4:7 In the days of Artaxerxes also, Bishlam, Mithredath, Tabel, and the rest of their companions wrote to Artaxerxes king of Persia; and the letter was written in Aramaic script, and translated into the Aramaic language.