Did the early Church know anything of this doctrine?

The Catholic Answers

St. Augustine, in the 4th century, wrote, “When it is a matter of sin we must except the holy Virgin Mary, concerning whom I will have no question raised, owing to the honor due to Our Lord.” St. Ephrem, also in the 4th century, taught very clearly the Immaculate Conception of Mary, likening her to Eve before the fall. The Oriental churches celebrated the feast of the Immaculate Conception as early as the 7th century. When Pope Pius IX. defined the Catholic doctrine in 1854 he gave, not a new truth to be added to Christian teaching, but merely defined that this doctrine was part of Christian teaching from the very beginning, and that it is to be believed by all as part of Christian revelation.

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