1602 (MDCII) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Friday of the Julian calendar, the 1602nd year of the Common Era (CE) and Anno Domini (AD) designations, the 602nd year of the 2nd millennium, the 2nd year of the 17th century, and the 3rd year of the 1600s decade. As of the start of 1602, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.