The Roman Eucahrist: What Does Vatican II Say?

Vatican II wrote on the Eucharist,

Christ is always present in His Church, especially in her liturgical celebrations. He is present in the sacrifice of the Mass, not only in the person of His minister, “the same now offering, through the ministry of priests, who formerly offered himself on the cross,” but especially under the Eucharistic species.
At the Last Supper, on the night when He was betrayed, our Savior instituted the Eucharistic Sacrifice of His Body and Blood. He did this in order to perpetuate the sacrifice of the Cross throughout the centuries until He should come again.
In the house of prayer the most Holy Eucharist is celebrated and preserved. There the faithful gather, and find help and comfort through venerating the presence of the Son of God our Savior, offered for us on the sacrificial altar (The Documents of Vatican II, Walter M. Abbott, S.J., General Editor. (Chicago: Follett, 1966), pp. 140-141, 154, 543).