Often abbreviated as CE, C.E. or c.e.
The Common Era is often known as the Christian Era and is used to number years. For instance the year 1999 is the one-thousane nine-hundred and ninety-ninth year of the Common Era.
Though Merriam Webster claims that the term originated in 1889 it has only become politically correct to use it instead of anno Domini to denote years.
It is the Christian Era it is based on the birth of Christ.