Would 1362 be Middle English? From the Online Etymology Dict.:

contra - 1362, from L. contra (prep. and adv.) "against," originally "in comparison with," ablative singular feminine of *com-teros, from Old L. com "with, together" + -tr, zero degree of the comp. suffix -ter-. The L. word was used as a prefix in L.L.; in Fr. it became contre- and passed into Eng. as counter-. The Nicaraguan Contra "anti-Sandanista" (1981) is short for contrarrevolucionario "counter-revolutionary."

http://www.etymonline.com/c8etym.htm