When we talk about the Indian history timeline, we always use the terms BC and AD to refer to the period when a particular event occurred.
In the timeline, time is measured from the birth of Jesus Christ. Using this system, they describe any event they require.
Full form:
12 BC = 12 years before Christ. Years BC counts backwards.
It means that years with larger value BC happened before years with smaller value years BC.
Julius Caesar
Born: 100 BC
Died: 44BC
Years AD count forwards.
AD 45 = 45 years after the birth of Christ.
AD starts just after Jesus’s birth, not his death.
Important Rules:
25 BC, 366 BC
AD 454, AD 321.