When we explore historical dates, we frequently encounter the terms AD and BC. These are key elements of the Gregorian calendar, which Pope Gregory XIII introduced in 1582. Today, it is the most widely used calendar system globally. The varied origins and adoption times of BC and AD highlight how our methods of recording history have evolved. This blog will explore how AD came about, when BC was first introduced, and their significant roles in shaping our understanding of historical timelines.
Before AD’s introduction, various cultures used unique systems to mark the passage of years. The Romans, for example, identified years based on their ruling officials, like “the year of Caesar and Brutus.” Similarly, the Greeks referred to years based on Olympic festivals, such as “the third year of the 74th Olympiad.” Meanwhile, the ancient Egyptians counted years by the reign of their pharaohs, with announcements like “Year 3 under the majesty of Pharaoh Ramesses II.” These systems, though effective locally, varied widely and lacked a universal approach to timekeeping.
Dionysius Exiguus introduced the term ‘AD,’ which stands for ‘Anno Domini’ or ‘In the Year of Our Lord,’ in the 6th century. His goal was to create a standardized method for calculating Easter. He chose Latin, the scholarly and ecclesiastical language of the time, and based the new calendar on the estimated year of Jesus Christ’s birth, marking it as AD 1. Dionysius aimed to distance the Christian community from the Diocletian system, which started counting years from the beginning of Emperor Diocletian’s reign. Known for severely persecuting Christians, Diocletian’s era was considered an inappropriate reference for a faith-based community. Dionysius’s calendar, centered on the life of Jesus, sought to unify and strengthen Christian identity across the Roman Empire.
While Dionysius introduced AD, significant refinements came with the Gregorian calendar, introduced by Pope Gregory XIII in 1582. This reform addressed the Julian calendar’s inaccuracies, especially in calculating Easter, which had become misaligned due to errors in leap year calculations. The Gregorian calendar improved long-term accuracy by adjusting the leap year system and realigning Easter with the spring equinox. It not only standardized year measurement across the Christian world but also became the globally adopted system, influencing civil life and governance.
Dionysius did not create a system for documenting years before Christ’s birth. He focused instead on recalibrating the calendar from the year he identified as Jesus Christ’s birth, marked as AD 1. As historical research evolved, the need to systematically record events before this starting point became evident. This led to the introduction of ‘BC,’ which stands for ‘Before Christ,’ first used by English scholars in the early 17th century. While “AD” originated from Latin, reflecting its scholarly and ecclesiastical roots, “BC” emerged as English became the predominant language in global scholarship and governance. This terminology allowed historians to organize and demarcate historical events before Dionysius’s established starting year.
In the late 20th century, the terms “BCE” (Before Common Era) and “CE” (Common Era) started gaining traction, primarily within scholarly and academic circles. These terms, which align numerically with BC and AD, were adopted to promote a more secular approach to historical analysis.
The evolution of the BC/AD dating system, with its integration of Latin and English terms, demonstrates how historical language and cultural layers influence our time-measuring tools. The adoption of secular terms like BCE/CE reflects broader changes in global scholarship. As historical study and communication continue to evolve, so will the terminology we use, adapting to new trends in academic research and global discourse.