The works of Homer (i.e. Iliad and Odyssey) and Hesiod (i.e. Theogony) were written in the 8th century BC, becoming the basis of the national religion, ethos, history and mythology.
What was the foundation for spirituality and church ? 
The works of Homer (i.e. Iliad and Odyssey) and Hesiod (i.e. Theogony)