Every city state had its one patron god but also a sanctuary to the other gods, and every person in ancient times was free to choose and form his own personal cult. Greek polytheism was a religious system prevailing from the 8th century BC until the 4th and 5th century AD, when replaced by Christianity. It was practically the same religion practiced by the Etruscans and the Romans – that’s why we are giving some of the roman equivalent names of the Greek Gods. Ancient Greek religion and the Greek Gods slowly disappeared in the early Middle Ages under the advance of Christianity and mainly when Christians took over the Roman Imperial Authority and imposed the closure, the neglect and destruction of many of the ancient sanctuaries, the sack of religious documents and the pillage of sacred objects.