How can I find out more about Dodekatheism?
Not only do thousands of primary works survive from the period of pre-Christian Greece, but academics and historians have been writing on the topic of ancient Greek religion for centuries. There are ample resources available to assist you in your exploration of ancient Greek religion. One needs to be critical with anything used as a source, because not all published works (even by academics, ancient writers or university presses) are accurate.
