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 at Pteria. It was the usual practice in those days for the armies to disband for winter and Croesus did so accordingly. Cyrus did not, however, and he attacked and defeated Croesus in Thymbria and later in Sardis, eventually capturing him. It became clear that the powerful empire destroyed by the war was Croesus's own.