There has been some confusion on the months of our calendar. The prefixes that have named a few of the months are the main problem. The prefixes Sept-, Oct-, Nov- and Dec- mean 7, 8, 9 and 10, respectively. However, the name's values are two less than the actual values. Why is that? Let's look into why in the world the names of some of the months have been moved.
This started with the Roman calendar, which started in March, meaning that the names were correct at some time. But there were only ten months that didn't add up to the solar year. The Roman calendar that was supposed to start in the spring was shifted way off balance. Julius Caesar, the leader of Rome at the time, saw this dilemma, and made some changes to the calendar. He added the months Ianuarius and Februarius to the end of the year, which made the calendar year balance out. He also made the change of the New Year being on January 1st and the end of the year being on December 31st. This was used as the modern calendar until 1582 AD.
The Julian calendar was still incorrect by 1582 and Pope Gregory XIII, the Pope at that time, reformed the Julian calendar so that the calendar would run at maximum efficiency. Unfortunately, Protestants who saw the calendar thought that Gregory wanted Christians to worship God on different days, and therefore called him the "Roman Antichrist." Gregory's calendar, called the Gregorian calendar, wasn't adopted in Europe until the 18th century.
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