Bishop (AKA "Saint") Nicholas's Present to the Arch-Heretic Arius: a Strike on the Face

The real "Saint" Nicholas was not necessarily always 
a jolly man - especially when it came to heretics 
attacking the deity of Christ. 

Arius, known for attacking the deity of Christ, was one of the world's greatest heretics. The biblical, Christian position affirms Christ's eternal deity (He took upon Himself a human nature in the Incarnation to be both fully God and fully man). But Arius attacked the truth that Christ has been God from all eternity by teaching that he was just a being created by God. 

It is believed that Bishop Nicholas (270-343) (whom the Santa Claus myth is inspired by) delivered a present to Arius for this wickedness: a strike on the face. 

The Nicholas/Arius incident is said to have occurred during the Council of Nicaea (325), which eventually, and rightfully, affirmed Christ's deity in the Nicene Creed. Arius, so the story goes, while defending his anti-Christ position, began singing a blasphemous song opposing the true Christ of Scripture. 

Nicholas had had enough; he approached the wolf in sheep's clothing and struck him (possibly in the mouth—the very instrument that Arius used to promote his damnable teaching).

Whether or not Nicholas' actions were warranted, and assuming this account is true, surely anyone concerned about the glory of God can understand Nicholas' outrage. He wanted to silence a man teaching blasphemous lies about Christ which led countless souls astray. 

What should have happened is that the state should have silenced Arius (per its duty to use the sword to suppress blasphemers and promoters of damnable heresy) so that Nicholas would not have felt the need to do so himself. 

Below is a summary of how the incident is believed to have occurred; note that accounts may differ as to whether it was a punch or a slap (either to the face in general, or to the mouth in particular):

Arius, a popular Alexandrian preacher, began teaching that Christ was inferior to God. He taught that Jesus was ... an intermediate spirit creature which was enfleshed—neither God nor even quite human. 

Arius spread his ideas by setting them to the music of drinking songs which were popular at pagan orgies.  

His most well-known song, disparaging the Incarnation and birth of Christ, was "Thalia." It bordered on the obscene, but the tune was so catchy that soon virtually everyone was whistling it in the streets and markets. 

"So scandalous did the situation become that in the very theaters of the unbelievers the venerable teachings of God were exposed to the most shameful ridicule," said Eusebius. 

Confessors, who had survived the persecution as Nicholas had, preached and reasoned with the people about Jesus, pointing to such Scriptures as:

For in Christ all the fullness of the Deity lives in bodily form ...

Anyone who has seen me has seen the Father ...

The Word became flesh and made his dwelling among us ...

The Son is the radiance of God's glory and the exact representation of his being ...

All this doctrine was to no avail. Arianism appealed to minds that reasoned that since they could not understand the Trinity, there could be no Trinity.

Constantine called a council of church leaders at Nicaea to discuss whether or not Jesus is really God, the teachings of Arius, and other matters dividing the church. ...

Legend has it that in the course of his presentation to the Council, Arius began to sing the "Thalia." Some of the bishops rushed out of the meeting. Others covered their ears.

St. Nicholas walked slowly to the center of the floor where Arius sang—and deliberately punched him in the mouth!

The shocked bishops sympathized with Nicholas but could not condone his action. ...

They deprived Nicholas of his bishopric (he was later restored to office) and they expelled Arius. Before the council ended, they wrote the Nicene Creed ...

John Cowart, Strangers on the Earth: A Collective Biography of People Whose Faith Got Them Into Trouble (Jacksonville, FL: Bluefish Books, 2005), 15, 16.