300

The year 300 (CCC) was a leap year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantius and Valerius. The denomination 300 for this year has been used since the early Middle Ages / Medieval period, when the Latin language term / abbreviation "Anno Domini" for the calendar era became the prevalent universal / worldwide method for naming and numbering years. First beginning in Europe at the end of the Roman Empire (after the split of the Western Roman Empire and Eastern Roman Empire in the early Middle Ages / Medieval period.