Christmas, the annual commemoration of the birth of Jesus Christ, is Thursday, Dec. 25.
Historians believe the holiday originated in Rome in the year 336. As Christianity spread across the world, the celebration of Christmas became more widespread and the holiday evolved to include both religious and cultural traditions, such as exchanging gifts, decorating trees and family gatherings.
In the United States, President Ulysses S. Grant signed legislation that made Christmas a federal holiday in 1870. The law applied only to federal workers and the District of Columbia, but the observance of Christmas as a legal holiday was eventually adopted by all states.
The U.S. Post Office Department released its first Christmas stamp in 1962.
The release started a tradition of extending seasonal greetings with stamps honoring secular and religious holidays.
