Before Christ, meaning the pre‐Christian era in the Gregorian calendar, running backwards from the year 1 bc as the year before the calculated, and back‐projected, year in which Christ was believed to have been born. The term is widely used in western societies in modern times, but when applied to prehistory it is simply the back‐projection of a relatively recent chronological system which cannot have had any meaning to ancient people. The use of lower‐case initials is often taken to indicate that the date has been calculated from a radiocarbon determination by subtracting 1950 from the radiocarbon age (sometimes expressed as RCYBC—Radiocarbon Years Before Christ). Although common in literature of the 1960s through to the 1980s, such a date is fundamentally wrong because radiocarbon years are not the same as calendar years and thus such calculations have been made without subtracting like from like. The use of upper‐case letters conventionally denotes a calibrated radiocarbon age in calendar years or, exceptionally, a historically determined age in calendar years. The alternative term BCE, meaning Before the Christian Era, is increasingly popular.