Apuleius says in the Florida, Section XV., in reference to Pythagoras,
that he went to Egypt to acquire learning, “that he was there taught by
the priests the incredible power of ceremonies, the wonderful
commutations of numbers, and the most ingenious figures of geometry; but
that, not satisfied with these mental accomplishments, he afterwards
visited the Chaldæans and the Brahmins, and amongst the latter the
Gymnosophists. The Chaldæans taught him the stars, the definite orbits
of the planets, and the various effects of both kinds of stars upon the
nativity of men, as also, for much money, _the remedies for human use
derived from the earth, the air, and the sea_ (the elements earth, air,
and water, or all nature).

“But the Brahmins taught him the greater part of his philosophy--what
are the rules and principles of the understanding; what the functions of
the body; how many the faculties of the soul; how many the mutations of
life; what torments or rewards devolve upon the souls of the dead,
according to their respective deserts.”

There is ample evidence, therefore, that the Greeks had communication
with, and borrowed the philosophy of, both Persia and India at a very
early date.

That there was intimate intercourse with India in very ancient times
there can be no doubt. In addition to the classical sources of
information collected chiefly by the officers of Alexander the Great,
Seleucus and the Ptolemies, and which was condensed and reduced to
consistent shape by Diodorus, Strabo, Pliny, and Arrian, within the
first century before and the first century after Christ, we have the
further proof of the fact by the constant finds of innumerable Greek
coins over a large portion of north-western India, and even at Cabul.