In Greek all pronouns go at the end or near the end of the sentence/phrase so it's kinda like:o Ελληνικός(Greek) θεός(god) μου(my) or in greeklish: o Ellinikos(Greek) theos(god)...
The Greeks belived in the Gods because they needed an explination for the forces and elements, but saw nothing. They couldn't do it themselves, so they thought supreme beings controlled them.