Ancient Calendars

• When the Ancient Egyptians noticed that the Dog Star (Canis Major) appeared near the sun every 365 days, they began keeping calendars based on this reoccurring interval. One of the first years ever recorded on their calendar was 3100 B.C.E. Up until the eighth century B.C.E. civilizations the world-over used 360-day calendars. But in the eighth century B.C.E, many civilizations either altered or got rid of these ancient calendars. Months were no longer set lengths but changed based on what people saw in the sky. "Priest-astronomers" would declare the beginning of a new month, and this usually happened when they first saw a new moon. Months were as long as the number of days between one crescent moon to the next.

Julian Calendar

• The oldest Ancient Roman calendar on record was a monthly calendar consisting of just ten months. It wasn't until 46 B.C. that Roman Emperor Julius Caesar introduced the Julian Calendar, with 365 days split into 12 months, and a leap day in February every fourth year. This monthly calendar lasted for a very long time: it was the most commonly used calendar in Europe until the late 1500's.

Gregorian Calendar

• In 1582, Pope Gregory XIII brought the Gregorian Calendar into action. The Catholic Church decided to modify the Julian Calendar to correct errors in synching the lunar calendar with the real Moon. This would allow for a more accurate scheduling of the feast of Easter. Many Catholic countries adopted the Gregorian Calendar soon after the Pope's decree, but Protestant nations, including the British Empire and the American colonies, didn't adopt it until 1752. Today, the Gregorian Calendar is the most widely used calendar in the world.

Recent Calendars

• 2005 Calendar -
  It was the warmest year ever recorded on planet Earth and also the costliest in terms of natural disasters. The 2005 calendar was packed with huge events that made history. Take a look at the year 2005 in review.
  
  2004 Calendar -
  From the archaeological discovery of tiny, fossilized humans to the admission no real threat from "weapons of mass destruction", 2004 was another year to remember. Take a look at some of the biggest 2004 calendar events that shaped history.
  
  2003 Calendar -
  The U.S. goes to war with Iraq and Arnold Schwarzenegger becomes governor of California. Also a year of major developments in medicine and healthcare - check out the 2003 calendar in review here.