The cuneiform texts from ancient Assyria and Babylonia that are preserved offer direct evidence for systematic astronomical observation in two widely separated periods. From the first half of the second millennium B.C., later tradition has transmitted the dates of successive Venus appearances and disappearances in the reign of a king of the First Dynasty of Babylon. From the middle of the eighth century B.C. to the middle of the first century B.C. are preserved a large number of fragments of astronomical diaries attesting extensive daily observations of naked-eye astronomical phenomena.