The abbreviation BCE stands for "Before Common Era" and refers to the period of history before the date that Western tradition ascribes to the birth of Jesus Christ. Sometimes this period is referenced as BC, or "Before Christ."
For many centuries, the abbreviations BC and AD (Anno Domini) were used to denote the year; however, in recent years the terminology was changed to Before Common Era (BCE) and Common Era (CE) in an effort to separate the notations from religion. This system can be visualized as a time line upon which the supposed date of the birth of Christ is zero. Any date following year zero is followed by CE, while dates preceding it are followed by BCE.