Today in 1582 the pope announced a new style of calendar. Known as Gregorian, it’s the one we follow today, complete with leap years and leap centuries (only years ending in 00 that are also divisible by 400 are leap years – so 2000 was one, but 2100 won’t be.) The new calendar recognised that the year wasn’t exactly 365.25 days long and, therefore, needed rectifying. The decree also meant that later that year 4th  October was followed by 15th October – a shame if you had a party planned for then.

Image © The Trustees of the British Museum