Pax Calendar

The Pax calendar was invented by James A. Colligan, SJ in 1930 as a perennializing reform of the annualized Gregorian calendar.

Design

Unlike other perennial calendar reform proposals, such as the International Fixed Calendar and the World Calendar, it preserves the 7-day week by periodically intercalating an extra seven days to a common year of 52 weeks = 364 days.

The common year is divided into 13 months of 28 days each, whose names are the same as in the Gregorian calendar, except that a month called Columbus occurs between November and December. The first day of every week, month and year would be Sunday.

In leap years, a one-week month called Pax would be inserted after Columbus.

To get the same mean year as the Gregorian Calendar it adds a leap week to 71 out of 400 years. It does so by adding the leap week Pax to every year whose last two digits make up a number that is divisible by six or are 99. Years ending with 00 have Pax, unless the year number is divisible by 400.