CE is an alternative to the AD, system used by Christians but the numbers are the same: this year is 2021 CE or equally AD 2021 (but usually we just say "this year is 2021"). AD is an abbreviation of . People who are not Christian may not be willing to accept that a religion should be named when a date is written. For this reason, another way to write a date was needed. The name Christian Era () is another name for Common Era.