Roman Catechism 18.175

Chapter 18 — Part II: The Sacraments — The Holy Eucharist

Section 175. Proof From The Council Of Trent — With regard to the institution of this Sacrifice, the holy Council of Trent has left no room for doubt, by declaring that it was instituted by our Lord at His Last Supper; while it condemns under anathema all those who assert that in it is not offered to God a true and proper Sacrifice; or that to offer means nothing else than that Christ is given as our spiritual food.