In the fifth century B.C., after Jonah's preaching of conversion and repentance, the town of Ninevah proclaimed a fast and put on sackcloth, and the king covered himself with sackcloth and sat in the ashes (Jonah 3:5-6). 550 B.C.) wrote, 'I turned to the Lord God, pleading in earnest prayer, with fasting, sackcloth, and ashes' (Daniel 9:3). Prophesying the Babylonian captivity of Jerusalem, Daniel (c. Job (whose story was written between the seventh and fifth centuries BC) repented in sackcloth and ashes (Job 42:6).
For instance, in the Book of Esther, Mordecai put on sackcloth and ashes when he heard of the decree of King Ahasuerus (or Xerxes, 485-464 B.C.) of Persia to kill all of the Jewish people in the Persian Empire (Esther 4:1). Ashes symbolized mourning, mortality and penance. The liturgical use of ashes originates in the Old Testament times.
