Gregory XIII elected pope – May 14, 1572
This week marks the anniversary of when Ugo Boncompagni was elected head of the Roman Catholic Church, eventually taking the name of Pope Gregory XIII.
A native of Bologna, Gregory XIII founded multiple seminaries, championed the arts, and, most notably, oversaw the creation of a new Western calendar, now known as the Gregorian calendar.
The Gregorian calendar was created in response to the shortcomings of the Julian calendar, which had been in use for centuries, but lacked a proper system of leap years.
"The papal bull issued by Pope Gregory XIII in 1582 decreed that 10 days be skipped when switching to the Gregorian calendar. However, only five countries adopted the new calendar system that year—namely, Italy, Poland, Portugal, Spain, and most of France," explained timeanddate.com.
“Since the discrepancy between the Julian calendar year and the astronomical seasons kept growing over time in the centuries that followed, more days had to be skipped in countries that switched to the Gregorian calendar in later years.”