In 1772 I think it was, the world lost 11 DAYS when it changed from the Jullian calendar to the Gregorian calendar!!! I only know this because it was on a trivia question on the ferry in Brisbane today!!!
First, it was the British Empire that lost the eleven days (including the North American colonies). And second, it was 1752.
The first countries to adopt the Gregorian calendar lost ten days in 1582, and the last ones to do so lost thirteen during the last century.
The Gregorian calendar was a great fix, but, since Pope Gregory was Catholic, the Protestants and Eastern Orthodox were afraid to go along. Russia didn’t change until after the 1917 Bolshevik revolution.