In 431 A.D.(that is approximately 140 years before the birth of Muhammad-pbuh.) at the Third Ecumenical Council, these teachings were accepted by Christians.
” Jesus Christ revived his being with the intelligent spirit and gathered them with a body to become a human being. So in a real meaning Saint Mary, the mother of Jesus Christ is the mother of the God.”
It is obvious that the mother of the God, is the God!
According to the Catholics, “her motherhood is not over yet”. With recurring intercession of hers, she continues to ensure the gifts of eternal goodness. They say “Saint Mary works like a lawyer, a helper, and an intercessor at the church.” 
Because of these words they turned Saint Mary into a god. But, one day Allah, the Almighty would command them:
“O Jesus, son of Mary! Did you say to the people: “Take me and my mother as two interceder deities besides Allah?” Jesus will say: “Exalted are You! It was not for me to say that to which is not right. If I had said it, You would have known it. You know what is within myself, but I do not know what is within Yourself. You are the only one who knows the unknown.” “
“I told them what you commanded me. Be the servants/ of Allah, my Lord and your Lord; I said. I witnessed them as long as I was among them. After you caused me to die, they were just under your observation. You are the witness over all things.” (Al-Ma’ida/ The Feast 5:116-117)
 Law of The Catholic Church