A monk called Dionysius Exiguus (early sixth century A.D.) invented the dating system most widely used in the Western world. For Dionysius, the birth of Christ represented Year One. He believed that this occurred 753 years after the foundation of Rome.
Dionysius Exiguus (also known as Dennis the Little or Dennis the Short) was a 6th century monk and historian. He is best known for creating the Anno Domini (AD) dating system, which is used to number the years in the Gregorian calendar (the calendar currently used in most of the world).
Dionysius was a monk in Rome and was asked to create a new system for dating events in order to determine the correct date for Easter. He decided to use the birth of Jesus Christ as the starting point for his dating system. He calculated that Jesus was born in the year 753 AUC (ab urbe condita, or “from the founding of the city” of Rome) and designated this year as AD 1.
Dionysius’ system was adopted by the Catholic Church and later spread throughout Europe, becoming the standard method of dating events in the Western world. However, there are some errors in his calculations and it is now believed that Jesus was actually born a few years earlier than Dionysius calculated. Despite this, the AD system is still widely used today.
Dionysius Exiguus is also known for his translation of the Easter table from the Greek into Latin, and for his collection of the canon law.