Pope Gregory XIII (r. 1572-85) is perhaps best remembered for introducing the calendar that bears his name.
On February 24th 1582, Gregory XIII issued a papal bull, Inter gravissimas, which modified the Julian calendar, introduced by Julius Caesar in 46 BCE. It came into effect later in the same year when October 4th was followed by October 15th, leading many to accuse the pope of stealing ten days from their life!
My name is David Lown and I am an art historian from Cambridge, England. Since 2001 I have lived in Italy, where I run private walking tours of Rome.
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