Year 1000 (M) was a leap year starting on Monday (link will display the full calendar) of the Julian calendar. It was also the last year of the 10th century as well as the last year of the 1st millennium of the Christian era ending on December 31st, but the first year of the 1000s decade. Popular culture sometimes holds the year 1000 as the first year of the 11th century and the 2nd millennium, due to a tendency to group the years according to decimal values, as if a year zero were counted. According to the Gregorian Calendar, this distinction falls to the year 1001, because the 1st century was retroactively said to start with year 1. Since the calendar has no year zero, its first millennium spans from years 1 to 1000, inclusive.