The use of BC and AD for numbering calendar years was invented by Dionysius Exiguus in 525 AD. His purpose was to determine the correct date for Easter under the direction of Pope St. John I. While most people recognize the terms B.C. and A.D. to mean, "Anno Domini" (or Year of our Lord referring to the year of Christ’s birth) and "BC" as Before Christ, I've devised a new system, specifically for my garden.
A.D. = After Dog