Here he wrote a defence of the doctrine of the Real Presence against the Calvinists in the form of an apology for Rupert, abbot of Deutz (Apologia pro Ruperto abbate Tuitensi, Paris, 1669).
The part that he was allowed to take in the drawing up of doctrinal formularies in Henry VIII.'s time is not clear; but at a later date he was the author of various tracts in defence of the Real Presence against Cranmer, some of which, being written in prison, were published abroad under a feigned name.
The suspected theses included such points as the following: that Christ descended ad inferos not in His real presence but quoad effectum; that no image or cross should receive latreia even in the sense allowed by Thomas; that it is more reasonable to regard Origen as saved than as damned; that it is not in a man's free will to believe or disbelieve an article of faith as he pleases.
At the council of Tours (1054) he found a protector in the papal legate, the famous Hildebrand, who, satisfied himself with the fact that Berengar did not deny the real presence of Christ in the sacramental elements, succeeded in persuading the assembly to be content with a general confession from him that the bread and wine, after consecration, were the body and blood of the Lord, without requiring him to define how.
Frohnleichnamsfest), a festival of the Roman Catholic Church in honour of the Real Presence of Christ in the sacrament of the altar, observed on the first Thursday after Trinity Sunday.
He had abandoned Luther's doctrine of consubstantiation and adopted the doctrine of a Real Presence conditioned by the faith of the recipient.