Tag Archives: Pope

5 – 14 October 1582: the ten days that never existed

Published in Blog (in English)

In 1582 Pope Gregory XIII issued the bull Inter Gravissimas with which he introduced the modification of the calendar that will take his name, the Gregorian Calendar. Until then, the Julian Calendar had been in force, introduced by Giulio Cesare in 46 BC. The modification was based on the calculations made by the Polish astronomer…