Gregorian Calendar

About the Gregorian Calendar

The Gregorian calendar, introduced by Pope Gregory XIII in October 1582, is the most widely used civil calendar in the world today. It was designed to correct the drift in the Julian calendar by refining the leap year rule, ensuring better alignment with the solar year.

📅 Key Features

• 365 days in a year - Divided into 12 months
• Leap Year Rule - A year is a leap year if divisible by 4, except for years divisible by 100 (unless also divisible by 400)
• Solar Calendar - Based on Earth's revolution around the Sun
• Week System - 7-day weeks with Sunday or Monday as the first day depending on region
• Universal Adoption - Standard for international communication, business, and civil purposes

🎉 Major Holidays & Observances

• January 1 - New Year's Day - Celebrates the beginning of the calendar year
• February 14 - Valentine's Day - Day of love and affection
• March/April - Easter - Movable Christian holiday celebrating resurrection of Jesus
• July 4 - Independence Day (US) - Celebrates American independence
• October 31 - Halloween - Traditional harvest festival with modern celebrations
• December 25 - Christmas Day - Christian celebration of Jesus' birth
• December 31 - New Year's Eve - Farewell to the old year

🌍 Historical Significance

The Gregorian calendar replaced the Julian calendar, which had accumulated a 10-day error by the 16th century. Different countries adopted it at different times - Catholic countries in 1582, Protestant countries gradually over the next centuries, and Orthodox countries as late as the 20th century. Today, it serves as the de facto international standard.

📊 Month Structure

• January (31 days) - Named after Janus, Roman god of beginnings
• February (28/29 days) - Shortest month, from Latin 'februum' (purification)
• March (31 days) - Named after Mars, Roman god of war
• April (30 days) - Possibly from Latin 'aperire' (to open)
• May (31 days) - Named after Maia, Roman goddess of fertility
• June (30 days) - Named after Juno, Roman goddess of marriage
• July (31 days) - Named after Julius Caesar
• August (31 days) - Named after Emperor Augustus
• September (30 days) - From Latin 'septem' (seven)
• October (31 days) - From Latin 'octo' (eight)
• November (30 days) - From Latin 'novem' (nine)
• December (31 days) - From Latin 'decem' (ten)