Pope Gregory XIII announced the Roman Catholic Church was changing over to a new calendar On This Day in 1582. The announcement was made through his papal bull Inter gravissimas. The new calendar, now used throughout most of the world, is known as the Gregorian calendar. It replaced the Julian Calendar.
On This Day is a prompt I started this month to further explore historical events.
© Jeanne Ruczhak-Eckman, 2015