1525 (MDXXV) was a common year starting on Sunday of the Julian calendar, the 1525th year of the Common Era (CE) and Anno Domini (AD) designations, the 525th year of the 2nd millennium, the 25th year of the 16th century, and the 6th year of the 1520s decade. As of the start of 1525, the Gregorian calendar was 10 days ahead of the Julian calendar, which was the dominant calendar of the time.