‘Astronomy in Antiquity’ traces the origins of astronomy, which emerged for different reasons in Egypt and Babylon. In Egypt the far-flung kingdom required a well-established calendar to ensure good administration. Whilst in Babylon the security of the throne depended on the correct reading of omens, including those in the sky. Allied to this was Babylonia's development of arithmetic. The Greeks took up these ideas, initially by Aristotle and others, and combined it with their own development of geometry, and this was later refined by Ptolemy, whose work Almagest synthesizes much of the thinking that had gone before him.