Transubstantiation
Transubstantiation is the Catholic Church's theological term for the change of bread and wine into the actual Body and Blood of Christ during the Eucharistic prayer of the Mass, even though their outward appearance remains unchanged.
A Change in Substance, Not Appearance
The Church teaches that the deepest reality ("substance") of the bread and wine changes into Christ, while what can be measured or tasted ("accidents" — color, taste, texture) stays exactly the same.
When Formalized
While rooted in Scripture and early Christian belief about the Eucharist, the term "transubstantiation" itself was formally defined at the Fourth Lateran Council in 1215.
Related Saints
Frequently Asked Questions
Is transubstantiation just a Catholic idea?
The doctrine in this precise philosophical form is distinctly Catholic, though belief in Christ's real presence in the Eucharist is shared, in varying ways, by Eastern Orthodox and some other Christian traditions.
Do Catholics believe the bread stops looking like bread?
No — its physical appearance, taste, and composition remain completely unchanged; the Church holds that what changes is invisible.