 Complete the following phrase:  The oracles also advised Croesus to find out which Greek state was most powerful and to ally himself with it. Croesus, now feeling secure, formed an alliance with Sparta in addition to those he had with Amasis II of Egypt and Nabonidus of Babylonia, and launched his campaign against the Persian Empire in 547 BC. The scholar Evans in 1978 examines the conflicting dates implied in Herodotus. Croesus was intercepted near the Halys River in central Anatolia and an inconclusive battle was fought 