1731

1731 (MDCCXXXI) was a common year starting on Monday of the Gregorian calendar and a common year starting on Friday of the Julian calendar, the 1731st year of the Common Era (CE) and Anno Domini (AD) designations, the 731st year of the 2nd millennium, the 31st year of the 18th century, and the 2nd year of the 1730s decade. As of the start of 1731, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923.