Karl Popper identified Xenophanes of Colophon (570−478 BCE) as the originator of the method of conjectures and refutations. This essay explores this claim, and the methods of both philosophers (section 1). Disparagement (ancient and modern) of Xenophanes has been misguided (section 2). Xenophanes, a critical rationalist and realist, pioneered philosophy of religion (section 3) and epistemology (section 4), but his method was not confined to falsificationism, and appears compatible with inductivism and abductionism (section 5). The method employed by Popper in interpreting Herodotus in support of his conjectures about Xenophanes is typical of the multiple-strand reasoning characteristic of the humanities, and is as much inductivist...