Historical Asides

A0: Dates and Times

Last updated 06/04/2022.

| A1

Julian Calendar

On this website, all dates before 1582 refer to the Julian calendar, which was in use in Dante’s time. In 1300, the Julian calendar was eight days behind the modern Gregorian calendar (introduced in 1582). In most historical work, it is customary to use Julian dates before 1582, to avoid confusion with the dates found in primary sources.

  • Example

    • Julian: April 7, 1300

    • Modern: April 15, 1300

New Year’s Day

In the Middle Ages, March 25 was the first day of the new year. On this website, dates are converted so that January 1 is the first day of the new year (in keeping with the modern standard). This means that all dates from January 1 to March 24 will appear to be one year ahead of the dates in primary sources.

  • Example

    • Medieval: January 27, 1301

    • Modern: January 27, 1302

Why March 25? Because it holds symbolic and theological significance. March 25 approximates the vernal equinox, the first day of spring; it is symbolic of new life and new beginnings. In the theological tradition, March 25 was believed to be the day God created the universe; the day of the annunciation in 1 BC (when the archangel Gabriel announced to the Virgin Mary that she was pregnant, notably nine months before December 25); and the day of the crucifixion of Jesus in AD 34 (see, for example, Hippolytus’ Commentary on Daniel 4.23.3).

Time of Day

In medieval Christian timekeeping, sunrise marked the beginning of a new day (as opposed to modern timekeeping, in which midnight marks the beginning of a new day). The day was divided into 24 hours, with names associated with every third hour (called “canonical hours,” set aside for daily prayer).

  • 00 (~06 AM) Prime (Sunrise)

  • 03 (~09 AM) Terce

  • 06 (~12 PM) Sext (Noon)

  • 09 (~03 PM) Nones

  • 12 (~06 PM) Vespers (Sunset)

  • 15 (~09 PM) Compline

  • 18 (~12 AM) Matins (Midnight)

  • 21 (~03 AM) Lauds

But whereas modern hours are defined as equal divisions (1/24) of a full day, medieval (canonical) hours were defined as equal divisions (1/12) of the time between sunrise and sunset. That is, the 0th hour is defined at sunrise, and the 12th hour is defined at sunset, with equal divisions in between. So in the summer (when daylight lasts longer in the northern hemisphere), daytime hours were longer than nighttime hours; while in the winter, daytime hours were shorter than nighttime hours. Moreover, the length of an hour would also depend on latitude (summer daylight is longer, and winter daylight is shorter, the farther north you go).

You can imagine what a nightmare this would be for precision timekeeping in the modern sense. But in the days before mechanical (or digital) clocks and synchronized schedules, it made perfect sense to give times relative to something everyone could see (the position of the sun). To say something happened at 6 AM means little without synchronized clocks; but to say it happened at sunrise is immediately understood.

Incidentally, in biblical (Hebrew) timekeeping, sunset (not sunrise) marks the beginning of a new day. This may play into the timeline of Dante’s journey through the afterlife.

The discrepancy between medieval and modern timekeeping is rarely an issue in the historical background, but I try to make it unambiguous when an issue does arise.