The dates of Croesus’ reign, traditionally 560–546, derive mainly from the Nabonidus Chronicle, for Cyrus’ conquest of Lydia, and Herodotus 1.86.1, that Croesus ruled Lydia for 14 years. Part I of this essay questions the reliability of 1.86.1's ‘14’. Herodotus often uses formulaic or traditional numbers, including seven, for dating and elsewhere. Seven, twice seven, 14 and 70 recur frequently in the Croesus logos. Croesus’ reign may be a formulaic twice seven: seven prosperous years before Solon's visit, followed by seven disastrous years. It therefore may be unhistorical. Part II adduces other passages in Herodotus, and other evidence, that Croesus ruled Lydia already in the 580s. Nothing dates Alyattes after 585. Part III considers possible consequences of redating Croesus for the dates of early electrum and bimetallic coinages, the latter beginning perhaps in the 570s, as does Croesus’ Artemision at Ephesos. Part IV doubts what happened to Croesus when Sardis fell. Herodotus adapted one version for his own purposes. He probably invented Croesus’ role as wise warner to Cyrus and Cambyses.