"The first instance of the formal invocation of Mary occurs in the prayers of Ephraim Syrus († 379), addressed to Mary and the saints, and attributed by the tradition of the Syrian church, though perhaps in part incorrectly, to that author. "
http://prayerfoundation.org/why_protestants_dont_pray_to_mary.htm
http://prayerfoundation.org/why_protestants_dont_pray_to_mary.htm