800 (DCCC) was a leap year starting on Wednesday of the Julian calendar, the 800th year of the Common Era (CE) and Anno Domini (AD) designations, the 800th year of the 1st millennium, the 100th and last year of the 8th century, and the 1st year of the 800s decade. As of the start of 800, the Gregorian calendar was 4 days ahead of the Julian calendar, which was the dominant calendar of the time.
