Consecration

[Churchman25]

When it comes to the consecrated host, who came up with the specific process that is
involved, so that the host becomes consecrated?

I understand at the last supper Jesus told his Apostled take this bread and wine and drink for this is my body and blood which will be shed for you and for all.

 

[PaulfromIowa]

It is called Transubstantiation.

Wikipedia:
en.wikipedia.org/wiki/Transubstantiation

The Catechism on the Eucharist:
vatican.va/archive/ccc_css/archive/catechism/p2s2c1a3.htm

1333 At the heart of the Eucharistic celebration are the bread and wine that, by the words of Christ and the invocation of the Holy Spirit, become Christ’s Body and Blood. Faithful to the Lord’s command the Church continues to do, in his memory and until his glorious return, what he did on the eve of his Passion: “He took bread. . . .” “He took the cup filled with wine. . . .” The signs of bread and wine become, in a way surpassing understanding, the Body and Blood of Christ; they continue also to signify the goodness of creation. Thus in the Offertory we give thanks to the Creator for bread and wine,154 fruit of the “work of human hands,” but above all as “fruit of the earth” and “of the vine” - gifts of the Creator. The Church sees in the gesture of the king-priest Melchizedek, who “brought out bread and wine,” a prefiguring of her own offering.155

 

[Crusaderbear]

Jesus himself “came up with it” at the Last Supper. If you mean the specific formula used at every mass - that is probably dated back to Peter himself when the mass was established after the Ascension.