BC and AD are the two most commonly used notations to denote the dates of historical events. However, most ancient civilizations did not use this method of marking dates. The Christian calendar was introduced in Rome only when the
converted to Christianity. This system of dating is still used internationally.

What is the question? Bc is Before Christ But is sometimes refers to as BCE Which means Before Common Era, AD means After Death

Explanation:

1. BC and AD 2. Roman emporers

Explanation:

bloodiest single day of war   |   gettysburg

where the civil war ends for good   | appomattox court house

the first major land battle; south wins | bull run/manassas (va)

gives union control of the mississippi river |   vicksburg

lee’s first tactical defeat; big win for union |   fort sumter1

with lincoln's re-election |   atlanta

south wins

splits confederacy in two for the duration of the war,

antietam