How do bc dates work

The addition of the B. There was no year zero. However, zero did exist; our modern conception of zero was first published in A. The idea would not spread to medieval Christian Europe, however, until the 11th to 13th centuries. The B. By the 15th century, all of Western Europe had adopted the B. In other words, October in the year was 1, Then calculate This means 4, years before October A. Claire is a writer and editor with 18 years' experience. She writes about science and health for a range of digital publications, including Reader's Digest, HealthCentral, Vice and Zocdoc.

How to Calculate Age in Lunar Years. How to Calculate Days From a Date. How to Find a Sales Trend Percent. How to Calculate Military Time. Calendar Year vs. Earth Orbit. How to Find Simple Interest. For example, the Romans generally described years based on who was consul, or by counting from the founding of the city of Rome. So Anno Domini , the year of our Lord, is a very easy transition to make, as opposed to dating the year an emperor had reigned in Rome. One of the early writers to date this way was Dionysius Exiguus, a monk who, in A.

Practical use of A. But, even as it grew, people continued to use other systems like the Roman calendar. But, Hunt says, B. Denis Petau , used the idea of ante Christum in his work De doctrina temporum. New editions continued to be published throughout the rest of the century and it was translated into English, where the abbreviations of A.

Another option was to use the Julian Period system invented in the 16th century by Joseph Scaliger, who combined several other calendars to come up with a master calendar that stretched nearly 5, years back before the year one.