The Oracle of Delphi was the best-known of the Greek oracles. Croesus, famed for his wealth and alleged inventor of coinage, wanted to know which oracle was most accurate, and so he tested them in the following way. To each oracle he sent a messenger, and informed them that, on the hundredth day after their departure, they were to ask the oracle to whom they had been sent what he, Croesus, was doing at that moment. They were then to write down the answer given and return home to Lydia.
Croesus, determined to come up with an activity that couldn’t be guessed by chance, had cut up a tortoise and a lamb and then cooked them in a cauldron of bronze. Only the Delphic Oracle correctly guessed this activity, and was rewarded with Croesus’s extremely generous patronage.
At this time, Cyrus the Great was forming his empire, and Croesus saw in him a threat to his own mighty empire. However, he feared the results of such a contest, and so inquired of the oracle whether or not he should attack Cyrus. He also asked whether his kingdom would last for a long time. To the first question, the oracle told him that, should he attack Cyrus, he would destroy a mighty empire. To the second, he was told that his kingdom would only fall when a mule ruled the Medes.
Bolstered by these answers, Croesus attacked Cyrus, and was defeated. The empire he had destroyed was his own, and the mule was Cyrus himself, for his father was Persian and his mother Median, and on account of this fact was called a mule, whose parentage is similarly mixed. His first conquest had been the Medes, a people whom the Greeks were consistently unable to distinguish properly from the Persians, a mistake perhaps comparable to the Anglosphere’s inability to grasp the difference between Dutch and Deutsch. And so in this way, a mule ruled the Medes.
Of course, the accuracy of the oracle is called into question by the simple fact that, had Croesus been victories, she could still have claimed to be right, since Cyrus’s empire had fallen, and the Medes were not ruled by a beast.