January 1 1583: First New Year of Gregorian Calendar

 January 1

1583: First New Year of Gregorian Calendar

The calendar established by Julius Caesar in 45 BCE was running ten days behind the real seasons of the year. Easter arrived too late in spring.

All because the Earth year is about eleven minutes short of 365¼ days. Without a calendar correction, Easter would eventually have fallen in summer, and Christmas in the spring. So Pope Gregory XIII appointed a commission. It proposed eliminating three leap years every four centuries (years ending in 00, unless divisible by 400). That would prevent further creep of the calendar against the seasons. But to reset the calendar immediately, ten days had to be eliminated. The pope decreed the new calendar should start in October 1582. The day after October 4 would not be October 5, but October 15.

This was just months away. Only Italy, Spain, and Portugal made deadline. Many people feared their lives were being shortened by ten days. The pious worried that saints might not listen to prayers that were ten days late. Everyone’s birthday moved up ten days too, so 365 days would pass between one birthday and the next. Rents, interest, and wages had to be discounted for that October, since it now had only twenty-one days.

A mob in Frankfurt rioted against the pope and his mathematicians. France made the change in December. Parts of the Low Countries jumped from December 21, 1582, directly to January 1, 1583, skipping Christmas. Most Catholic countries adopted the Gregorian calendar by 1584. But Europe became a patchwork of calendars. You could cross a border and go backward or forward ten days. (Makes the international date line kid stuff.) The Julian calendar (see here) held on until 1752 in Britain and its colonies, and right through 1918 in Russia.

As a result, the old Soviet Union used to celebrate its October Revolution in November.—RA

Also January 1:

1801: Piazzi Discovers Ceres, First Known Asteroid

1845: Telegraph Helps Capture Murderer John Tawel

1915: Aspirin Tablets Replace Powdered Form (see here)