This study analyzes the reception of theories of the "first principle" of Thales, Anaximander, and Anaximenes (7th-6th century BC) by Aristotle and his commentators of the 2nd through 14th centuries AD. It includes a detailed discussion of 120 texts documenting this fascinating and, for the modern image of the Milesians, fundamental Wirkungsgeschichte of the earliest philosophical ideas of Europe.