From the Breviary of Prague, 1502, the continuation of the Bull “Transiturus” of Pope Urban IV, promulgating the feast of Corpus Christi, read in the Divine Office for the lessons of Matins during the octave.
This bread is received, but not truly consumed, it is eaten, but not changed, since it is not transformed within the one who eats; but if it be worthily received, to it is the receiver conformed. O most excellent sacrament! which we must venerate, adore, worship, glorify and love, magnify with special praises, exalt with worthy hearts, honor with all zeal, accompany with devout service, and remember with sincerity. O most noble memorial! which we must commend to the depth of our hearts and diligently keep therein, bind firmly to our minds, and recall with constant meditation and celebration. We must celebrate the memory of this (sacrament) continually, that we may be always mindful of Him, whose memorial we know it to be; for the memory of one whose gift or favor is the more often seen, must be the more strictly kept.
Therefore, although this sacrament in His memory is frequented in the daily solemnity of the Mass, nevertheless we deem it fitting and worthy that at least once in the year, the memorial thereof be kept with greater celebration and solemnity, especially to confound the unbelief and insanity of the heretics. For on the day of the Lord’s Supper, on which day Christ Himself instituted this sacrament, the universal Church, being very much occupied with the reconciliation of the pentients, the making of the sacred Chrism, the fulfillment of the commandment concerning the washing of the feet, and other things, cannot be fully free for the celebration of this greatest sacrament.
“To confound the unbelief and insanity of the heretics.” St Norbert, the founder of the Premonstratensian Canons, was a great promoter of Eucharistic devotion, (one of the characteristic features of his order,) well over a century before Pope Urban IV promulgated the feast of Corpus Christi. He is often depicted trampling upon the heretic Tanchelm, the founder of a bizarre sect which denied any value or purpose to the Blessed Sacrament; his fanatical followers in the Low Countries seem to have been taught to worship Tanchelm himself, and venerate his bathwater as a relic. St Norbert was called into the neighborhood of Antwerp to oppose the heresy, which he succeeded in suppressing; the Premonstratensian Order order traditionally kept a feast called “The Triumph of St. Norbert” shortly after the Octave of Corpus Christi to commemorate this event. (Statue in St. Peter's Basilica by Pietro Bracci, 1767)
