system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why we count years in terms of C.E. and B.C.E.
gpt
The Roman Catholic Church, which controlled a major portion of the civilized world for over a thousand years, adopted the Julian Calendar, which is similar to the calendar that we have today. They started counting from the supposed birth of Jesus, calling the new period AD and the period before his birth as BC. 

The calendar was later changed a little, and is now called the Gregorian Calendar. The reason the terms BCE (before the common era) and CE (common era) are used is because BC and AD sound religious.