In the mid 500’s BCE Pisistratus became a tyrant (authoritative leader) in Athens. Because he had the power he ordered all farmers to switch from grain production to olives. Grain production was never very productive due to the poor soil but olive vines prospered. Athens now became a leading producer of olive oil and it could easily buy all the grain it needed. Another result of this switch was that pottery production increased to hold the oil and Athens became a the leading  utilitarian and ornamental pottery producer as well. During his reign he also brought bards together and created the definitive version of the Homeric legends that is close to what we know today.

(The Great Courses – The Long Shadow of the Ancient Greek World)