Dionysius Exiguus

Dionysius Exiguus (c. 500-560), Latin for Dennis the Short, is the Roman monk who invented anno Domini (“in the year of the Lord”) or AD, also known as the Common Era or CE. It counts years from the birth of Jesus Christ, making this year 2019.

He came up with AD in AD 525 when Pope John I asked him to figure out the date for Easter for the coming year.

Easter back then fell on the first Sunday after the first full moon of spring, but not on Nisan 14th on the Hebrew calendar (in which case it fell on the following Sunday) – hardly something an ordinary person could figure out in advance.

Alexandrian Easter tables: Although Dionysius was an accomplished mathematician and astronomer, he pretty much just translated Easter tables from Alexandria and updated them to cover the next 102 years.

anno Diocletiani: The Alexandrian Easter tables numbered the years according to anno Diocletiani, in the year of Diocletian, where year 1 was the year he became Roman emperor, what we call AD 284. It has been used by the Coptic Church in Egypt to this day. It is also called Anno Martyrum because Diocletian killed so many Christian martyrs.

anno Domini: When Dionysius translated and updated the Easter tables he replaced anno Diocletiani with anno Domini because, instead of counting years from the rise of an evil emperor, he:

“preferred to count and denote the years from the incarnation of our Lord, in order to make the foundation of our hope better known and the cause of the redemption of man more conspicuous.”

The birth of Jesus Christ: According to Scripture, Jesus was born in the time of King Herod. King Herod died in 4 BC – so Dionysius was at least four years off, probably more like six or seven. But he used the best knowledge of the time.

The year zero: There is no year zero because the invention of zero had not yet arrived in Rome from India. That would take at least another 600 years.

From his Easter table in Rome in 525 the use of AD slowly spread. In 731 Venerable Bede became the first historian to use it. Charlemagne became the first ruler to officially use it, crowned by the pope on Christmas Day in AD 800.

Friends: Boethius, Cassiodorus.

Day job: Cassiodorus said Dionysius was “most learned in both languages”, meaning Latin and Greek. He translated Church documents from Greek to Latin, especially canon law. He started that under Pope Gelasius I, the last African pope as of this writing (AD 2019). Among other things, he translated a book about the history and discovery of John the Baptist’s head.

A map of the Black Sea in AD 500. The Byzantine Empire is in pink, the province of Scythia on the sea’s western shore. (Via roman-emperors.org)

Birthplace: He was called a “Scythian monk”. That was something of a school of thought within church circles, but most of them did in fact come from Scythia Minor, a Byzantine province at the mouth of the Danube River, now part of Romania and Bulgaria. Ethnically he was probably a Latin-speaking Thracian, people who will become Romanians.

– Abagond, AD 2019.

See also:

• AD (Anno Domini)
• calendars
  • Julian calendar
  • Gregorian calendar
  • Hebrew calendar
  • Alexandrian calendar
• zero
• Jesus Christ
• Easter
• Byzantine empire
  • Roman Egypt
    • Alexandria
• Cassiodorus
• Boethius
• Romanization
• Romanian

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