1613 (MDCXIII) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Friday of the Julian calendar, the 1613th year of the Common Era (CE) and Anno Domini (AD) designations, the 613th year of the 2nd millennium, the 13th year of the 17th century, and the 4th year of the 1610s decade. As of the start of 1613, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.