The shrine of Dodona was regarded as the oldest Hellenic oracle, possibly dating to the second millennium BCE according to Herodotus. Situated in a remote region away from the main Greek poleis, it was considered second only to the oracle of Delphi in prestige. Priestesses and priests in the sacred grove interpreted the rustling of the oak (or beech) leaves to determine the correct actions to be taken. As for "when" those actions should be taken... one merely had to wait for a breeze and it was obvious even to the oracle's petitioner.
The Problem of Those Who Wait.–Happy chances are necessary, and many incalculable elements, in order that a higher man in whom the solution of a problem is dormant, may yet take action, or “break forth,” as one might say–at the right moment. On an average it does not happen; and in all corners of the earth there are waiting ones sitting who hardly know to what extent they are waiting, and still less that they wait in vain. Occasionally, too, the waking call comes too late–the chance which gives “permission” to take action–when their best youth, and strength for action have been used up in sitting still; and how many a one, just as he “sprang up,” has found with horror that his limbs are benumbed and his spirits are now too heavy! “It is too late,” he has said to himself–and has become self-distrustful and henceforth for ever useless.–In the domain of genius, may not the “Raphael without hands” (taking the expression in its widest sense) perhaps not be the exception, but the rule?–Perhaps genius is by no means so rare: but rather the five hundred hands which it requires in order to tyrannise over the “the right time”–in order to take chance by the forelock!-Nietzsche, "Beyond Good & Evil" (274)