Christ's birth as base of our calendars

Dear Matthew Alice: I’ve checked the library; I have asked experts, but I can't find the answer anywhere. So as a last resort, I seek the wisdom of Matthew Alice. At what point in history did Western civilization begin reckoning time from the birth of Christ? — Justus Curius, Vista

I’m just as curious to discover who your “experts” were. Make a note to have them defrocked if they couldn’t answer this one. Again I warn — hang around with unlicensed know-it-alls, you get what you deserve.

The evolution of the world’s calendars is a stupefying litany of calculations and recalculations by centuries of astronomers, kings and popes, with a little superstition thrown in. The colorful 12-page thing on your wall, the one with the beach bunny nuzzling the Fram oil filter, is the Gregorian calendar. It’s a slight tweaking of the Julian calendar, the first official calendar of the Holy Roman Empire, adopted in what we’d now call A.D. 325. The year-numbering system came a little later. It was the monk Dionysus Exiguus in A.D. 525 who devised the idea of the “Christian Era,” counting years consecutively from the Annunciation, simply as a way to solve the problem of figuring the date for Easter. Venerable Bede’s Ecclesiastical History of the English People popularized the B.C./A.D. system as a secular application for marking years, but it wasn’t widely and officially adopted for another ten centuries. Dionysus was a little off in his calculations; scholars believe Christ was actually born somewhere between 8 and 4 B.C., according to the current system.