Gregorian calendar: The modern calendar —commonly referred

The modern calendar —commonly referred to as the Gregorian calendar —is the internationally accepted civil calendar used today in most parts of the world. It evolved from earlier calendars developed over millennia, including the Roman calendar and the Julian calendar . The Gregorian calendar was introduced in 1582 by Pope Gregory XIII to reform the previous Julian calendar , which had become misaligned with the seasons. Here is a detailed history of how the modern calendar came into ... The Gregorian calendar was introduced in 1582 by Pope Gregory XIII by reforming Julian Calendar . Gregorian Calendar , also known as New Style Calendar . Description The Gregorian calendar , like the Julian calendar , is a solar calendar with 12 months of 28–31 days each. The year in both calendars consists of 365 days, with a leap day being added to February in the leap year s. The months and length of months in the Gregorian calendar are the same as for the Julian calendar . Learn about the Gregorian calendar , the most used calendar system in the world today, based on the earth's orbit around the sun. Find out its history, rules, seasons, holidays and yearly calendars for the future and past years.