The post 5 Unique Historical Facts About Calendars appeared first on Calendar. Calendar. 5 Unique Historical Facts ... By 2400 B.C., Sumerians had stepped up their game to devise a pseudo-monthly ...

The Sumerians were among the most inventive of ancient civilisations – and laid the foundations for the more advanced societies that were to follow. They lived in the fertile valleys between … ...

The origin of leap years. Many ancient populations, including the Sumerians, Chinese and Romans, created calendars based on phases of the moon. While lunar calendars do a good job of tracking ...

Over time, the Sumerian calendar became increasingly out of sync with the seasons. Around the same time, Egyptians invented a solar calendar of 365 days a year, comprised of three four-month seasons, ...