Maybe this is a dumb question, I never really gave it much thought until someone else in the office mentioned it in passing. So, "BC" starts at Christ's birth and works backwards in time. "AD" starts at Christ's death and moves forward in time. It's generally agreed upon that Jesus died sometime in his 30's -40's right? So, that leaves a few decades that are neither BC or AD, when he was alive. What's the term for this period of time?