Ethiopia thirteenth month. The Ethiopian months begin on the same days as those of the Coptic calendar, but their names are in Ge'ez. Like the Julian calendar, the sixth epagomenal day—which in essence is a leap day—is added every four years without exception on 29 August of the Julian calendar, six months before the Julian leap day. Thus, the first day of the Ethiopian year, 1 Mäskäräm, for years between 1901 and 2099 (inclusive), is usually 11 September (Gregorian), but falls on 12 September in years before the Gregorian leap year. Also, a seven- to eight-year gap between the Ethiopian and
Calendar reform entirely, to make the calendar perennial. Around 1930 Colligan invented the Pax Calendar, which avoids off-calendar days by adding a 7-day leap week to the 364-day common year for 71 out of 400 years. In 1993, Lloydine and José Argüelles founded the World Thirteen Moon Calendar Change Peace Movement. Dividing the years into 52 weeks creates 13 months of 28 days (4 weeks), and 4 quarters of 91 days (13 weeks). This creates months and quarters of fixed, even duration, but not quarters containing a whole number of months. Instead of a leap week or an extra day and a