Calendars of the World How Do We Measure Time?

Dates Dates allow us to place events in correct order and identify events that happened at the same time

Christian Calendar Based on the supposed year of Historical Jesus’ birth (year Jesus born should be Year 1) Years before His supposed birth are marked B.C. (Before Christ); Years after His supposed birth are marked A.D. (Anno Domini “Year of our Lord” in Latin)

A BC Timeline An AD Timeline

Christian Calendar 1-100= 1st Century AD 101-200= 2nd Century AD 201-300= 3rd Century AD 1901-2000= 20th Century AD 2001-2100= 21st Century AD (etc.)

Islamic Calendar Based on the year Mohammed returned to Mecca, Saudi Arabia and converted city to Islam (holiest city in Islam)

Islamic Calendar Hijrah: Year 1 on the Islamic Calendar (622 AD on Christian Calander) This is the year of city of Mecca’s conversion to Islam

Jewish Calendar Based on the year that they believe God created the earth (3761 BC on Christian Calendar) Year 2000 AD was 5761 on Jewish Calendar

Julian Calendar Calendar we use now in the Western World Roman Emperor Julius Caesar needed the whole empire on the same schedule for taxing purposes (1st Century BC)

Julian Calendar Julian Calendar first to recognized a year as 365.25 days (leap years come later)

Julian Calendar Next Roman Emperor Augustus changed 7th month’s name to July (to honor Julius Caesar) took a day from February to make July 31 days changed 8th month’s name to August (to honor himself) No Year 0 in Julian Calendar

Julian Calendar BC 300-201=3rd Century 200-101= 2nd Century BCE (Before Common Era) 100-1= 1st Century BCE (Before Common Era) 1-100= 1st Century CE (Common Era) 101-200=2nd Century CE (Common Era) 1901-2000= 20th Century CE (Common Era) 2001-2100= 21st Century CE (Common Era)

Final Thought on Calendars Remember that calendars are arbitrary, made and manipulated by people to serve their needs