At the time, a priest named Arius (from the theologically extravagant city of Alexandria) attempted to bring things “into line” with sober thinking about God with his approach to the big Jesus question. His attitude was summed up in the phrase “There was a time when he (Christ) was not.” In other words, Jesus Christ was not the true and co-eternal Son of God, but a kind of highly ranked creature. When some other “highly ranked” individuals (in the Roman Empire) espoused this view, Arianism spread through the Christian world, unsettling the social order to such a degree that Constantine (yes, that Constantine) called a council of the world's bishops to address the matter. The Emperor intended to take part in the council, too.
As the bishops went back and forth, studying various attempts to express the mystery of Jesus in terms that would be clear enough to grasp, while preserving the ultimate mystery, one unusual word kept coming up. It referred to the Son in the Trinity as “homoousios to Patri”: “one-in-being with the Father.”
It was highly controversial, but as the bishops kept looking at it, they agreed that introducing this non-biblical expression accomplished the task of protecting the biblical message.
We recite those words weekly, and usually without incident. But when the bishops at Nicea signed on to that newly minted Creed (perhaps based on the Palestinian baptismal creed), they had reason to fear for their lives. (Almost fifty years years later, St. Ambrose made his famous crack about the fish-mongers and butchers arguing over the divine and human natures in Christ, and they probably didn't limit their arguments to theological terminology.)
St. Nicholas of Myra held fast to the truth about Jesus. Apart from that message and the mystery it proclaims, we really have no reason to celebrate Christmas with all the gusto we reserve for the most festive moments of life. And so, for his daring role in protecting the real meaning of Christmas for us, I am happy to keep a place in my Christmas for the great St. Nick!