Did you know that Dickens wrote A Christmas Carol in six weeks, more or less, and published it himself in an act of depressed desperation? S'True. Complementarily to Frank's link above, you'll learn a little more on the creation of what would become, arguably, the most important book in terms of modern Christmas as we know it. Hans Werner fills in the remaining blanks; and, for this lovely review, let us raise our vices in a treasure-trove of thanks or two. In Canada, as the entire world most likely knows, we "celebrate" Boxing Day 26 December. Know why? Nope, neither do I; but, I do know the only day truly worthy of celebration in this household falls on 2 January (when the world returns to its regularly skedded insanities).
BTW, if Christ put in his earthly appearance in the middle of June, I (idly) wonder if that explains why Joyce chose the sixteenth of that month for what we now call Bloomsday. Hrm . . .