Daniel 9:1-3

These things happened during the first year Darius son of Xerxes was king over Babylon. He was a descendant of the Medes. During his first year of rule, I, Daniel, was studying the Scriptures and noticed that according to the word YAHWEH had revealed to the prophet Jeremiah, seventy years must pass while Jerusalem lay in ruins. Then I turned my heart to the Lord God, seeking an answer from him, pleading for mercy with fasting, wearing sackcloth, and sitting among ashes.