This project investigated how natural phenomena in different realms of nature (celestial, medical, terrestrial) were interpreted as signs, and how the notion of natural sign changed in Babylonia and Greece, as evidenced by innovations in various textual corpora including Babylonian astronomical diaries, predictive astronomical methods (e.g. the Babylonian Goal-Year method and mathematical astronomy) and contemporaneous developments in astrology, other fields of divination and medicine. The main aims of the project were A: To establish a methodology of signs and its connection to modern concepts of causal reasoning; B: To map how theories underlying the interpretation of signs were actually used in various fields of reasoning.