Ages

'Time Periods'/levels each with a spell and technologies to go with it. The Classical, Heroic, and Mythic Age each have you worship the god at that age. Depending on the god you choose depends on the new myth unit you get, (and the upgrades that go with it) the technology upgrades you get, and your extra/new spell you get. The gods to choose are either all Greek, all Egyptian, or all Norse.