53 We have a wonderful example of the stability of the Catholic faith in the way in which these words meet with such complete agreement in the constant teaching of the Ecumenical Councils of the Lateran, Constance, Florence and Trent on the mystery of the Eucharistic conversion, whether it be contained in their explanations of the teaching of the Church or in their condemnations of error.
Source: Mysterium Fidei (Vatican.va)