The Julian calendar, introduced by Julius Caesar in 46 BC, was the primary calendar used in the Roman Empire and much of the Western world for over 1,600 years. It is a solar calendar with a year consisting of 365 days, with an extra day added every four years (leap year) to account for the Earth’s orbit around the sun.
Over time, the Julian calendar’s calculated year length of 365.25 days was found to be slightly longer than the actual solar year, leading to a gradual drift in the calendar’s alignment with the seasons. By the 16th century, the calendar had drifted by about 10 days, causing problems for religious festivals and agricultural practices.
