Just saw Mozart's opera Idomeneo last night live streamed from the Met to one of our cinemas in Chichester. For a 2nd string Mozart opera it was really brilliant as is this whole streaming programme. For very reasonable prices one can see the best in the world! However I have a stupid question that has been bothering me. This opera was set just after the Trojan war with the victorious Greeks on Crete. They worshiped Neptune , the God of the sea, but why, he was a much later Roman God - the Greeks would have worshiped Poseidon, surely Mozart and his librettist would have know this?