In the history book that I got for Christmas all of the dates have "CE" and "BCE". (i.e. 650 BCE or 1200 CE)

BCE means Before Common Era, and CE, of course, means Common Era.

BCE is equivalent in meaning to BC, and CE is equivalent to AD.

The reason for this change is to be religiously neutral. BC stands for Before Christ, and AD stands for a Latin phrase that means "in the year of our lord". Non-Catholics think "Well he's not my lord."