AD and BC
Sometimes you see Years written like
What does it mean?
|AD is AFTER Jesus was born|
|BC is BEFORE Jesus was born|
BC comes from Before Christ
Years Before and After
So, 550 BC means 550 years before Jesus was born
And 2000 AD almost means 2000 years after Jesus was born ...
... except AD started at 1, not 0
So, 2 AD is actually 1 Year after Jesus was born
And 2000 AD is actually 1999 Years after Jesus was born.
But we don't really know WHEN Jesus was born!
Some historians put the actual birth of Jesus 4 years earlier (4 BC), but it WAS thought to be exactly at 1 AD.
A monk named Dionysius Exiguus calculated his own present year to be 525 AD
And if you continue counting years from then you get our current year number.
So, AD is now just a "Year Number" (every New Year we add 1), and it only roughly equals how many years ago that Jesus Christ was born.
"2000 AD" or "AD 2000"
Should "AD" be written before or after the number?
It WAS common to write it before (the standard was to put "AD" before the year and "BC" after), but now many people put "AD" after the year number. So you decide!
What is CE and BCE?
They are recent terms that mean mean the same as AD and BC:
CE means "Common Era" and is the same as AD
Example: 2012 CE is 2012 AD
BCE means "Before Common Era" and is the same as BC
Example: 500 BCE is 500 BC
There are other ways of saying what year it is!
Example, Muslims have dates that relate to Mohammad's emigration from Mecca to Medina called the Hijra, and so they use AH dates. The Year 2012 AD is 1433 AH (but the years don't have an exact match, because AH years are shorter!)