In the 6th century CE, a Scythian monk named Dionysius Exiguus was sent to Rome. Dionysius may have taken the monastic nickname of “the small” (exiguus), but his humility sheathed both his incredible abilities as a translator of Greek and Latin and his mathematical skills. He wrote and translated numerous saints lives, transcribed debates on heresies, and was known for his work with canon law. However, what Dionysius would be remembered for was his modifications to the dating system used within the Church and his attempts to use tables, called a computus, in order to track the date of Easter.
As classicists such as Michele Salzman have shown, calendars have long allowed for the organization and creation of cultural memories. They are also tools of transition. Whether we are discussing the institution of the Julian calendar or the early Christian one, the structuring of time was and is a potent tool that could be used to underscore and to erase various persons and events. Similarly, Dionysius wanted to overhaul the starting point for the current era by beginning it with Christ’s birth, instead of conforming to the dating system instituted by the Church based on the era of the martyrs, which had counted forward from the 3rd century persecutor Diocletian (anno Diocletiani).
Dionysius proposed: ‘anno domini nostri Jesu Christi’ (in the year of our Lord Jesus Christ’). This would mean that the date he was writing, Anno Diocletiani 248, would become Anno Domini 532 with his new calculations. The redefinition of ‘A.D.’ was thus born in the West, though many other churches (like the Coptic church in Egypt) would continue to use Diocletian’s persecution as a marker of time and identity.
A second debate addressed by Dionysius had been raging since the second century: the date of Easter. As emeritus ancient historian Alden Mosshammer remarks in his book on Dionysius Exiguus, the term ‘computus’ was applied to the science of reckoning the date of Easter. It would later influence the creation of the word ‘computer’, but it originally had a much more ecclesiastical definition. According to the Gospels, Easter had occurred on or near the Jewish feast of Passover, held on the first full moon on the first spring month of the Hebrew calendar.
Early theologians such as Hippolytus of Rome spent dedicated amounts of time attempting to compute the date of Easter. At the time, early Christians often used the Jewish Calendar to help them to date and set their own celebration of Easter. This point is expounded upon by historian of Rabbinic Judaism Sacha Stern in his book, Calendar and Community. Yet in the third century, anti-Jewish sentiment caused some early Christian theologians to compute Easter as a means of divorcing themselves from a dependence on the Jewish calendar. Within Ps.-Cyprian’s De Pascha Computus (On Computing the Paschal Feast) in 243 CE, he notes explicitly that Christians were sick of trailing after the “blind and stupid Jews” and thus wished to calculate Easter on their own. A late antique reminder that the creation of a calendar could express liberation, but also be born from prejudice.
While the Bishop of Rome set the date for Easter in the West after consulting with various scholars, churches in Asia Minor refused to honor these dates. The Council of Nicaea in 325 would decree that both the Eastern and Western churches should hold Easter on the same day, but alas, both calculated the easter cycle differently though both did agree that the celebration should be separated from the Jewish calendar and fall on the Sunday after the first full moon that followed the vernal (spring) equinox (March 21). In 525, Dionysius stepped in and told a bit of a fib about the council proceedings and ultimately accepted calculations for Easter developed in the fourth century CE. He then set dates for Easter with his own computus spanning from 532 to 627, a 95 year cycle.
Although there were still adherents to the Ionan Easter calendar into the medieval period, in the West, the Synod of Whitby (664) would further engrain the western Church’s date for Easter in Northumbria and elsewhere in modern Britain and Scotland. Even today, the Eastern Orthodox Church sets their own date for Easter. This year, it is on April 8. Bound up in this debate were not only aspects of mathematics, astronomy, and science, but also the basic notion that to control time was to assert dominance.
In concluding this blog post, I want to turn to my own obsession with calendrical control and some attitudes towards the calculation of time. As I have written about before on my blog and on Twitter, I prefer to use the notation of CE (Current Era) rather than AD as a more secular alternative–even if I do have a special place in my heart for Dionysius and for Late Antiquity. The use of CE is just one shift you may notice now that I am the editor-in-chief for the SCS blog, but there will be more. In my first post, I wanted both to introduce you, our readers, to my work as a historian of late antiquity, but also to note that there will be stylistic and content changes to the blog as the Communications Committee, SCS monthly bloggers, and other classicists contribute to the conversation in this space.
While I know that not everyone will agree on my editorial habits, I assure you that this remains an open but civil forum that welcomes people of all backgrounds and beliefs. In recent months, SCS’s social media pages have occasionally been plagued with racist, xenophobic, and sexist remarks that reveal a rather toxic online environment that can lurk under the surface of the internet. But this is not something that has to be tolerated. Just as these remarks won’t be allowed according to our social media policy, this blog will similarly remain a space that represents and emphasizes inclusion. That being said, we do want to hear what you have to say. So pitch us a story and make your voice heard within the SCS community. We may not always agree on polticial, religious, or social issues (or even the date of Easter) but I do think we can come together to underscore the import of Classics and community in the modern world.
History From Below 
I would like to start with how much I love your articles. They are engaging, well researched, and refreshingly open to new perspectives in the classical world. I would like to challenge (or at least nuance) the use of Common Era in place of Anno Domini. The change from one to the other seems to me to be motivated by an attempt at inclusivity in our discussions of history and to move away from a Christian-centric focus. This strikes me as misguided, however, because CE still revolves around the Christian notion that the birth of Jesus marks a strong contrast and division in the “Era” we are in, so as to make everything which follows the Common Era. This use of the term is every bit as centered around Christian ideas of the import of Jesus Christ. While not referring to him as “Dominus” might be a slight improvement, by using the term CE instead we are masking the continued debt our calendrical system has to figures like Dionysius Exiguus. We disguise the centrality of Christian thought while at the same time perpetuating it through our use of terms like BCE/CE. I’m not calling for a reversion to AD, but instead a more careful reflection of the terms we use to understand history instead of blindly adopting these terms in our writing. As a Jew, I see people use CE and think themselves somehow enlightened socially conscious without truly understanding that they are still using following the same calendar. A rose under any other name would smell as Christian. It is highly implausible that our ways of talking about historical dates will change any time soon (imagine trying to get everyone on board with BP), we do need to pay attention to the terms we use and how they lithify, or at least perpetuate, a Christian-centric narrative.
This was in no way an attack on you or your choice to use CE (I imagine you have thought about this issue and consciously came to the decision), but only the thoughts of a lowly undergraduate on what I see to be a broader (albeit minor) problem in the field. I think too many people adopt this term without understanding what it still refers to.
Thank you for these nuanced thoughts. I appreciate them. You are definitely not a “lowly undergraduate” to my mind. If you look at my previous post on B/CE and this one too, I do indeed recognize that this is only a more secular version. It is, as you say, still predicated on Dionysius’ original system and thus is still tied to Christianity. I hear that and I hear you, but this is simply my preference. I welcome and invite people to use the system they feel most comfort with. I have done a lot of thinking about this in order to reach my own decision, and everyone should follow what they wish. For me? I will stick to B/CE.