I was relating much of this from memory so I cannot give you exact
references. Actually, Rene in his several messages has listed most of the
ancient Western mentions with their sources -- why don't you google for the
exact passages as most of these texts are available somewhere on the
internet, though I should warn you to beware of various eccentric theories
that crop up. There are also several books on ancient East-West encounters
which you should be able to find if you put in a little effort of your own.