Hope you had a blessed Epiphany! Western Christians follow the Gregorian calendar, named for the man who commissioned it in the 16th century, Pope Gregory XIII. But many Orthodox Churches still use the older Julian calendar to set the dates of liturgical feasts. So, if you are in Russia on January 7, these welcome words fill the air, “Khristos rozhdayetsia!” Christ is born! See Orthodox Christmas celebrations in pictures here.
The Julian calendar dates from the time of its namesake, Julius Caesar. It was a good calendar, but, over the years, people began noting its problems. The actual solstices and equinoxes, annual events marking the waxing and waning of hours of sunlight, did not match their calendar dates. People might be observing the shortest day of the year, but their calendar told them it actually occurred a few days later, when the days were growing noticeably longer.
So Pope Gregory XIII asked mathematicians to create a new calendar, which was ready for use in 1582. Though it’s hard for us to understand now, the new calendar became a matter of intense debate, all bound up in the battles of the Reformation. Should Protestants use a popish calendar? England, and its colonies, did not introduce the Gregorian calendar until 1752.
But it wasn’t all politics. In order to switch from the Julian to the Gregorian calendar, people had to skip ten days, just erase them from that year. A person might wake the morning after August 1 expecting it to be August 2. But it was, instead, August 11. Imagine trying to make such a change with computers and all their attendant devices. As it was, some feared the Roman Church had stolen ten days of their already short lives!
Today, almost everyone uses the Gregorian calendar. But, as we noted above, the Julian calendar is still in use in Christian Churches for feasts and fasts. If you want to figure the difference, keep in mind that there is a thirteen-day gap between the two calendars. And be sure to wish your Orthodox friends a very merry Christmas.