Both measure the number of years since the approximate birthday of Yeshua of Nazareth (a.k.a. Designation of a particular year in BC and BCE also have identical values.
For example, Yeshua is believed to have been born circa 4 to 7 BCE, (a.k.a. Many people assume that Yeshua/Jesus was born a few days before the end of December, during 1 BCE.
1 AUC is the same as 753 BC in the Julian calendar.
This history starts on the "Kalends of March" or March 1st with the introduction of the Roman calendar in the year 1 AUC (AUC stands for Ab Urbe Condita, meaning "from the foundation of Rome").
The method for calculating Easter date also mirrors calendar changes, so I have included that also.
Many thanks must go to Ron Mallen for his tireless, meticulous and scientific process in researching this history.
One is "CE Marking" which is a compulsory marking found on many products sold within the European Economic Area (EEA). The word "common" simply means that it is based on the most frequently used calendar system: the Gregorian Calendar.
"CE" found in this web site refers to the other meaning, the "Common Era." This meaning for "CE" is a synonym for "AD." The latter is an abbreviation for "Anno Domini" in Latin or "the year of the Lord" in English. BCE stands for "Before the common era." BC means "Before Christ," or "Before the Messiah." Both measure the number of years before the approximate birthday of Yeshua/Jesus.
This is demonstrated by early measuring rulers dating back as far as the 6th century BC.