Thomas Aquinas

Thomas Aquinas believed that, though the
elements of communion taste and look the
same as bread and wine (having the accidents),
once consecrated, they become the body and
blood of Jesus (new substance). This idea, which
groups like Catholics believe, is called Transubstantiation.
Since the principle of individuation is matter; while
God is immaterial: nor is He the subject of accidents,
so as to be called a substance.
•Aquinas, Summa Theologica 146