12 BC 12 BC Year 12 BC was either a common year starting on Saturday, Sunday or Monday or a leap year starting on Sunday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Friday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Messalla and Quirinius (or, less frequently, year 742 "Ab urbe condita"). The denomination 12 BC for this year has been used since the early medieval period, when the Anno Domini calendar era
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