Expert: Hank Hokamp - 9/14/2011

Question
QUESTION: Hi Hank,
Just wondering about time and calendars in the 5th Century.  Would people living in the 5th century have said they were living in 421 AD? That is, if someone was writing a letter would they have dated it 421?

ANSWER:
   The Julian calendar began in 45 BC (709 AUC) as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year (known at least since Hipparchus).

   The Julian calendar has a regular year of 365 days divided into 12 months with a leap day added to February every four years. The Julian year is, therefore, on average 365.25 days long. The motivation for most calendars is to fix the number of days between return of the cycle of seasons (from spring equinox to the next spring equinox, for example), so that the calendar could be used as an aid to planting and other season-related activities. The cycle of seasons (tropical year) had been known since ancient times to be about 365 and 1/4 days long.

   You would NOT use AD. It would read Wednesday 2, 47. (Example)

   * The Gregorian calendar was used in Europe, starting in 1852.

   Take care, my friend, and stay safe.

         HANK



---------- FOLLOW-UP ----------

QUESTION: You would NOT use AD. It would read Wednesday 2, 47. (Example) I don't understand this.

Answer

  Hi:

  Sorry, Anne. I forgot the month! I apologize, my friend.

  Immediately after the Julian reform, the twelve months of the Roman calendar were named Ianuarius, Februarius, Martius, Aprilis, Maius, Iunius, Quintilis, Sextilis, September, October, November, and December, just as they were before the reform.

  Earlier, no AD was needed. Then it was. So, how about: Ianuarius 4, 421 AD or 4 IANUARIUS, 421 AD?

         HANK