500 (D) was a leap year starting on Saturday of the Julian calendar, the 500th year of the Common Era (CE) and Anno Domini (AD) designations, the 500th year of the 1st millennium, the 100th and last year of the 5th century, and the 1st year of the 500s decade. As of the start of 500, the Gregorian calendar was 1 day ahead of the Julian calendar, which was the dominant calendar of the time.

It is one of only seven years to use just one Roman numeral. The seven are 1 AD (I), 5 AD (V), 10 AD (X), 50 AD (L), 100 AD (C), 500 AD (D), and 1000 AD (M).

• Possible date for the Battle of Mons Badonicus: Romano-British and Celts defeat an Anglo-Saxon army that may have been led by the bretwalda Aelle of Sussex (approximate date; suggested dates range from 490 to 510) Note: This battle may have influenced the legend of King Arthur
• Possible date at which Fergus I of Dalriada begins his reign
• Approximate beginning of the Heptarchy period in the history of England
• Approximate year of the founding of the Kingdom of Essex
• Emperor Xuanwu of Northern Wei China becomes sovereign of the Northern Wei Dynasty
• Uxmal founded (approximate date)
• Traders from southern Arabia settle in northern Ethiopia