Short answers, pulled from the story.
The church fixed the date of Christmas as December 25 in the early 4th century. The earliest document to place Jesus's birthday on this specific day is the Chronograph of 354, which was written in Rome in the year 336.
England's Puritan rulers banned Christmas in 1647 following the Parliamentarian victory over Charles I during the English Civil War. Christmas was restored as a legal holiday in England with the Restoration of King Charles II in 1660 when Puritan legislation was declared void.
Charles Dickens wrote the novel A Christmas Carol in 1843, which helped revive the spirit of Christmas and seasonal merriment. The instant popularity of the book played a major role in portraying Christmas as a holiday emphasizing family, goodwill, and compassion.
A series of informal truces took place for Christmas between opposing armies during the First World War, particularly in 1914. One of the most memorable images of the Christmas truce was the games of football played between the opposing sides on Christmas Day 1914.
The modern popular image of Santa Claus was created in the United States, and in particular in New York. The transformation was accomplished with the aid of notable contributors including Washington Irving and the German-American cartoonist Thomas Nast, who lived from 1840 to 1902.
Some jurisdictions of the Eastern Orthodox Church mark feasts using the older Julian calendar, which currently corresponds to January 7 on the modern Gregorian calendar. Since Christmas 1899 until Christmas 2099 inclusive, there is a difference of 13 days between the Julian calendar and the modern Gregorian calendar.