In 1550, Thomas Cranmer, then Archbishop of Canterbury, wrote a book on the subject of the Lord's Supper. For Cranmer the topic was one for which he had labored until he had significant expertise. The book, A Defence of the True and Catholick Doctrine of the Sacrament of the Body and Blood of our Saviour Christ, was written to be a thoroughgoing dismantling of the Roman Catholic doctrine of transubstantiation. Because of the circumstances of his birthplace and times, few men have seen like Cranmer both the corrupting power of error in this matter and the liberating strength of truth. Cranmer believed the satanic doctrine of transubstantiation was the root system of all the thick weeds that had grown up in the medieval church, choking the consciences of God's people, keeping them from the sweet and pure air of a wholly completed justification before God by faith alone. 
If the bread and wine cease to be bread and wine but rather become the real body and real blood of Christ, then Christ's work is not finished. Then the table is, as the Roman Church teaches, really an altar where the sacrifice of Christ for sin remains unfinished and thus the sinner's conscience is not purified once and for all. This is actually taught in the Catechism of the Catholic Church. Note especially articles 1366-1367 and 1371.
As the devil's doctrine of transubstantiation is propagated, the Lord's Supper becomes just another work worshipers perform again and again to chip away at their justification. How great is this dreadful diminishing of Christ!
Here is Cranmer in his book's Preface: 
...the roots of the weeds, is the Popish doctrine of Transubstantiation, of the real presence of Christ's flesh and blood in the sacrament of the altar, (as they call it) and of the sacrifice and oblation of Christ made by the priest for the salvation of the quick and the dead. Which roots, if they be suffered to grow in the Lord's vineyard, they will over-spread all the ground again with the old errors and superstitions. These injuries to Christ be so intolerable, that no Christian heart can willingly bear them. 
Cranmer goes on to say that it was not the heavenly Father who planted these weeds in his garden, but his adversary the devil, and Antichrist, the devil's minister. He means the Pope. 
Cranmer then says he cannot remain silent for on the day the Lord appears he would not know how to excuse himself if he did. He then adds: "God I take to witness that I take this labor for none other consideration, but for the glory of his name, and the discharge of my duty, and the zeal that I bear toward the flock of Christ." 
It would be Cranmer's zeal in this matter that would ultimately cost him his life. After a great surge in Reformational theology, England suffered a great setback when the Roman Catholic, Mary I, ascended to the throne. Later known as Bloody Mary, she put to death some 200 prominent Protestants during her reign, including Cranmer, primary author of the Book of Common Prayer and the Thirty-Nine Articles. 
On October 16 of 1555, Cranmer saw his dear friends and theological colleagues, Hugh Latimer and Nicholas Ridley, burned at the stake. Already under arrest himself, Cranmer decided to recant all his Protestant doctrines. The fear of death, he would later say, shamefully gripped him. Here is one historian's summary of Cranmer's moment of weakness before earthly powers:


Between the end of January and mid February 1556, Cranmer made four recantations, submitting himself to the authority of the monarch and recognising the Pope as the head of the church, but despite this his priesthood was taken from him and his execution was set for the 7th March.  Cranmer quickly made a fifth recantation in which he stated that he fully accepted Catholic theology and that there was no salvation outside of the Catholic Church, and announced that he was happy to return to the Catholic fold. This recantation and statement of faith really should have led to him being absolved but although his execution was postponed another date was soon set. This postponement simply allowed a final, public recantation to be organised at University Church, Oxford. [Source: Claire Ridgway, B.A. University of Warwick]

When Cranmer was brought in for his public recantation before being put to death, his courage was mightily restored to him, like Samson at his last hour among the Philistines. Cranmer's contemporary, John Foxe (1516-1587), records the brave moment Cranmer made public recantation of his previous recantations: 

And now I come to the great thing which so much troubleth my conscience, more than any thing that ever I did or said in my whole life, and that is the setting abroad of a writing contrary to the truth; which now I here renounce and refuse, as things written with my hand contrary to the truth which I thought in my heart, and written for fear of death, and to save my life if it might be; and that is, all such bills and papers which I have written or signed with my hand since my degradation, wherein I have written many things untrue. And forasmuch as my hand hath offended, writing contrary to my heart, therefore my hand shall first be punished; for when I come to the fire, it shall be first burned. As for the pope, I refuse him, as Christ’s enemy and antichrist, with all his false doctrine. As for the sacrament, I believe as I have taught in my book against the bishop of Winchester, which my book teacheth so true a doctrine of the sacrament, that it shall stand at the last day before the judgment of God, where the papistical doctrine contrary thereto shall be ashamed to shew her face.

The "book against the bishop of Winchester" is the same book discussed above. 
May the Lord grant us a modest and due measure of gratitude for men like Cranmer. Men who, in spite of their weakness, shined forth in the strength of Christ, testifying with their lives to the worth of Christ crucified once and for all for the justification of sinners. They were God's burning torches, lighting a path for Reformation according to the Word of God. May it please the Lord to raise up such men among us in our day, men who will be so jealous for the true doctrine of Christ they will not be ashamed to abandon false altars and attend true tables where Christ feeds his saints not to justify them - they being already justified by faith alone in Christ's perfect and full propitiation at Calvary - but to increase their faith in their knowledge of union with Christ.