Calendars have been used for thousands of years. The early ones were usually based on the phases of the Moon and the movement of the Sun. We still depend largely on the natural movements of the Earth, Moon and Sun to divide up time. The calendar we use today is based on the Julian calendar, which, was introduced by the Romans in 46 BC. It had 365 days, and the Romans had not yet discovered the need for leap years. By 1582 the Julian calendar was ten days out, and Pope Gregory decreed that ten days would have to go missing from that year. This caused rioting because people felt that ten days of their lives had been stolen.
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