Undoubtedly one of the few relics left to us of the songs of the Atlantean civilisation.The 1,2,3 bit is certainly the date of the final destruction of Atlantis, possibly by the explosion of the volcanic island Santorini. Some have said the reference is to 123BC as the date of the explosion, but this seems unlikely as in 123 BC they didnt know it was 123BC as BC had not been invented. The most we can say with any certainty is that the explosion happened 123 years after(or possibly before) something or other else. Anything more would be conjecture at this stage.