Fr. Scott A. Haynes
The Emperor Decius, who ruled the Roman Empire from 249-251 A.D., issued a proclamation in the second year of his reign, which tested the obedience of the people. This oath of loyalty for the population required absolute adherence. In the midst of a pagan culture, Christianity was illegal and considered a superstition (supersitio).
From the Emperor's point of view, Christians displayed “godlessness,” and so, Decius decided to issue an imperial edict ordering all citizens to make an “atonement” to the gods of Rome, which further proved personal loyalty to him and the state. It was the first such order in Roman history. Decius presented the Christian population with a life-changing choice:
“Sacrifice or I’ll make you sacrifice.”
Emperor Decius of Rome.
What was this sacrifice? It was a pagan sacrifice to the gods of Rome and to the Emperor. The sacrifices had to be performed in the presence of a Roman magistrate, who confirmed the sacrifice had been made. The magistrate signed an official certificate. While the exact text of the edict of text has not been found, numerous certificates of the magistrates are preserved even today.
In the face of this choice, some Christians refused. For this, they were tortured or martyred. Some tried to flee the reach of the Emperor. The lost their possessions and property. Most of the Christian population gave in to the evil demands of Decius and made pagan sacrifice to the false gods of Rome and presented the magistrate documents to attest to this.
Libellus from the Decian persecution 250 A.D., certifying that the holder has sacrificed to the Roman gods.
These lapsed Christians (lapsi) committed a mortal sin as they broke the first commandment. Offering worship to a pagan deity, they denied Christ, who said:
“Whoever denies Me before men, I also will deny before My Father who is in heaven” (Matthew 10:33).
Among the first victims of Decius was Pope St. Fabian. The Pope was interred in the catacomb of Callixtus in Rome and died there as a martyr on January 20, 250. St. Fabian was highly esteemed by St. Cyprian. St. Cyprian's letter to St. Fabian's successor, St. Cornelius, calls him “incomparable” and says that the glory of his martyrdom answered the purity and holiness of his life. 
Because of the persecution of the Emperor, the Chair of St. Peter was vacant (sede vacante) after the death of Pope St. Fabian. At last, after nearly eleven months, St. Cornelius was elected Bishop of Rome on March 6, 251, in the midst of the Decian persecution.
As the persecution was ongoing, no one could imagine how long it was be drawn out. Fortunately, the Decian persecution stopped after eighteen months with the death of the Emperor. At this point, many of the lapsed wished to rejoin the Church. Pope St. Cornelius and the Bishop of Carthage, St. Cyprian, whose feast is observed annually on September 16, decided to bestow mercy upon them.
St. Cyprian considered the persecution to be the Church's trial. The lapsed had failed this test, and in order to get back in touch with God, they needed healing. St. Cyprian wrote:
“My heart bleeds with each one of you, I share the weight of your sorrow and distress … when my brethren fell, my heart was struck and I fell at their side.” 
The reunion of the lapsed was something Sts. Cornelius and Cyprian sought, but two opposing forces fought against it. The first barrier was erected by the laxist party. The next by the rigorist. What Sts. Cornelius and Cyprian labored to find was the golden mean between severity and laxity.
The laxists decided the lapsed were to be allowed to partake in the Eucharist without delay. The laxists did not require the lapsed to be first reconciled in sacramental confession. They did not acknowledge the need for those who had denied Christ by pagan worship to be absolved of their sins prior to returning to Holy Communion. St. Cyprian comments:
“[The laxist indulgence] does not mean the granting of reconciliation but its frustration, it does not restore men to communion but bars them from it and from salvation.”
As Saint Paul teaches:
“You cannot drink the chalice of the Lord, and the chalice of devils: you cannot be partakers of the table of the Lord, and of the table of devils.” 
The laxists attempted to replace God's standard of mercy with their own criteria of mercy. Even if they had reception of the Eucharist:
“Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord.” 
St. Cyprian understood why penance is necessary because it offers a chance for glory, writing:
“He who has made such satisfaction to God, he who by his repentance and shame for his sin, draws from the bitterness of his fall a fresh fund of valor and loyalty, shall by the help he has won from the Lord, rejoice the heart of the Church whom he has so lately pained; he will earn not merely God’s forgiveness, but His crown.”
The other obstacle to peace was Novatian, who incited discord by portraying himself as the anti-Pope to St. Cornelius. Additionally, Novatian and his adherents substituted their own notions of mercy for God's. As rigorists, they would not consider any pardon for the lapsed who had offered false worship, nor for murderers or adulterers. St. Cyprian wrote:
“Novatian did what the Lord did not even grant to the apostles, [as he endeavored] to separate the chaff from the wheat.” 
Even St. Peter made the mistake of three times denying Christ, but after making threefold amends, Jesus forgave him. All who stand in the way of the reconciliation of sinners betray the Lord because He wants everyone to be saved and at peace with Him. As the Book of Numbers recalls for us:
“The Lord is patient and full of mercy, taking away iniquity and wickedness…” 
Sts. Cornelius and Cyprian provide an authentic witness to Christ-like mercy, which neither downplays the evil of sin, nor loses hope in its reparation. These great men insisted that the Church did have the power to forgive apostates and other sinners. And that they could be re-admitted to full communion after having performed an appropriate period of penance. St. Cornelius stated:
“There is one God and one Christ and but one Episcopal Chair, originally founded on Peter, by the Lord's authority. There cannot, therefore, be set up another Altar or another Priesthood. Whatever any man in his rage or rashness shall appoint, in defiance of the divine institution, must be a spurious, profane, and sacrilegious ordinance.” 
As we honor Sts. Cornelius and Cyprian, let us beg their intercession as we pray for those who have lapsed from the true faith will make a good and hearty confession and be reconciled unto Christ and to His Mystical Bride, the Church, sharing in the harmony and peace of God’s kingdom. As St. Cyprian wrote:
“You cannot have God for your Father if you do not have the Church for your mother.... God is one and Christ is one, and his Church is one; one is the faith, and one is the people cemented together by harmony into the strong unity of a body.... If we are the heirs of Christ, let us abide in the peace of Christ; if we are the sons of God, let us be lovers of peace.” 
 Cyprian, Epistle 30.
 St. Cyprian, The Lapsed.
 1 Corinthians 10:21.
 1 Corinthians 11:27.
 St. Cyprian, Letter 51.