There are many reasons to be thankful for the benefits of modern living ― antibiotics, airplanes, velcro . . . Another subtle but essential item is our calendar. It may have some frustrating moments, but consider how months used to work. Take heed of Mercedonius.
(The insertion of a leap day, week, or month into some years is called “intercalation.” Intercalation is done to align the calendar with the seasons or moon phases.)
The name Mercedonius comes from the Latin word “merces,” which means “wages.” It got its name because workers were paid at the time of year Mercedonius occurred, around the month of Februarius.
The addition of Mercedonius didn’t happen automatically. The decision was made by the high priest of the College of Pontiffs, who was also known as the Pontifex Maximus. The Pontifex Maximus, Latin for “greatest bridge-maker,” was the head honcho of the ancient Roman religion.
The Pontifex Maximus was supposed to base the decision whether to include Mercedonius in any given year so that the calendar would correspond with the seasons. Politics, however, are said to have motivated his decision making. For example, Mercedonius was sometimes inserted to allow a government official to stay in office longer.
You can imagine the confusion that this caused. If you were living outside of Rome, you might have no idea what the current date was.