With the New Year and our return to Ordinary Time in the liturgy it seems appropriate to explain the Church’s role in dating and time. Many of us take for granted the dates and times of the months and years, but where did we get our current calendar? Part of the answer reveals an important truth about Catholicism: that it is concerned with all aspects of human good, including the dating of time.
The Church has her own calendar marked by the seasons of Advent, Lent, Ordinary Time, and Easter, as well as various memorials, feasts, and solemnities. The Church also gave us our secular calendar with months, weeks, and days. In 1582 Pope Gregory XIII issued the new calendar in the papal bull Inter gravissimas. He did this to correct astronomical errors of the spring equinox in the Julian Calendar. The Julian Calendar originated with Julius Caesar and was the main calendar in use throughout Europe since the 1st century BC. Prior to the 1500s European scholars were aware of the error, but it was not until the 16th century that the growing discrepancy between the days and the seasons, required action. While the Gregorian Calendar is not perfect, it is much more accurate than the Julian Calendar. In approximately several thousand years it may require another rework (based on the slowing down of the Earth’s rotation and other factors).
Of course, the pope’s declaration, while based on astronomical and scientific observation, had no authority outside of Catholic realms and the Papal States. Other countries gradually adopted the calendar over the next hundred years. Initially, Protestant countries objected to adopting the calendar in opposition to the pope. For instance, Sweden adopted the Calendar two hundred years later in the 1700s. Interestingly, while the Gregorian Calendar is the most widely used civil calendar there are still countries which either do not use it or use it in conjunction with their own calendars. So, in addition to its role in salvation, the Church stands behind the dating of months and days.