1593 (MDXCIII) was a common year starting on Friday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1593rd year of the Common Era (CE) and Anno Domini (AD) designations, the 593rd year of the 2nd millennium, the 93rd year of the 16th century, and the 4th year of the 1590s decade. As of the start of 1593, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.