Read the Greeks on the 'Sirens' that is a great start also see the Bible referemces to the 'Cananites', Classical Roman Litrature - references abound - Hippocrates some refs ... hmmm ... there are some more .... old Celtic Language material lots of good stuff - see Tuatha De Dannan - gaelic Goltrai, Geantrai, Suantrai.

Modern practices can still be found in central Europe.