A Brief History of the Feast of Corpus Christi
Jesus lost many followers when he told the crowd that unless they eat (the actual word in greek means literally to gnaw) his body and blood they would have no life in them. One year later, the disciples celebrated their first Eucharist with the Lord himself presiding and saying to them, "Take and Eat, this is my body." Since this first Holy Thursday, the believers celebrated "the breaking of bread" knowing they were partaking in the actual body and blood of Christ.
Through the prayers of the priest (presbyters) invoking the Holy Spirit the elements are miraculously changed from wine and wheat bread, but still retaining the appearances of the same. This has not always been the easiest concept to accept. Saint Paul had to make it clear to the Corinthian believers that they were indeed partaking in the body and blood of Christ and a strict penalty was experienced for those who did not "discern it rightly." If a mere symbol was in play, why would believers get sick and even die as a result of taking the communion meal improperly?
The writings of the Church fathers are indisputable regarding the belief of the Real Presence and even Protestant Church historians admit that earliest Church belief was thoroughly "Eucharistic."
The apostle John, who leaned his head on Jesus' breast at the institution of the Eucharist, had a disciple under his tutelage named Ignatius. Ignatius of Antioch wrote in clear terms that the Eucharist was indeed the real body and blood of Christ, rebuking those who already began to distort its meaning. Many other early Church fathers including Augustine wrote voluminously on the sacrifice of the mass and the fact that Christ's real body and blood was truly present on the altar. Why call it an altar if there is no sacrifice?
For the next 900 years, the Church continued to celebrate the Eucharist, partaking in the actual body and blood of Christ with almost unanimous agreement as to the theology of this sacrament. Then, a priest named Berengarius from Tours began to question this belief and preached against the Real Presence but was corrected by the Church and repented of his error before he died in 1088.
In the 12th century a devout religious nun named St. Juliana from Liege, Belgium petitioned her bishop to designate a feast day to honor the most Blessed Sacrament and in 1264 the pope set a universal feast called Corpus Christi to honor Jesus in the Eucharist. Saint Thomas Aquinas was commissioned to write the office for the celebration/mass and his explanation of the change of substance from bread to Christ's body is still studied and marveled at today. No, the Church did not "invent" the concept of transubstantiation in the 13th century. The belief had always been there but was never so eloquently elucidated for the faithful as was accomplished by this brilliant and devout monk.
Fast forward to the Reformation. Luther has just opened his can of worms by declaring that one does not need the Church to tell one what to believe. Within 100 years of Luther's reformation, there was over 200 interpretations of the Lord's supper. To his credit, at least initially, Luther fought vehemently against the other reformers to insist that Jesus was truly present in the communion meal. When he realized his own flawed paradigm sola scriptura was being used against him by Zwingli and others to teach that the Eucharist was only symbolic, he resorted to Sacred Tradition to bolster his defense of the Eucharist. Sadly, his theology morphed further and he no longer held to transubstantiation at the end of his life. You know the rest of the story-only the Orthodox and Catholic Churches retain the original apostolic teaching of the Eucharist, that is, Christ is truly substantially present, body, blood soul and divinity in the Eucharist.
On the Eve of the Feast of Corpus Christi, I say this to my readers - If you want to get close to Jesus, become Catholic and experience him in the way that the apostles taught and believed. Jesus is waiting. We'll leave the light on for you.