This was a little math I did from one of my roleplaying blogs on Tumblr, for a female!Revan.
In the Old Republic timeline, the Treaty of Coruscant was so significant that it became year “0” and time was then calculated as events before the treaty (BTC) and after (ATC) - this was not, however, the last time that such a recalculation was made.
The Battle of Yavin during the Rebellion Era was another reset, becoming “year 0” with before (BBY) and after (ABY) which are the more common timeline measurements for general Star Wars things that focus on the movies and novels around or after that time.
However, given this is a Revan-centric blog, I find it necessary to post up a conversion between the two. Simply put, the Treaty of Coruscant is 3653 BBY. Therefore, the Battle of Yavin is 3653 ATC. So the initial math, where “X” is the years before or after the Treaty of Coruscant, looks like this:
- If “X” is BTC, then X + 3653 = BBY
- If “X” is ATC, then 3653 - X = BBY
Of course, if you want to do it in reverse and figure out how to turn the dates based on the Battle of Yavin into the Old Republic Era, it’s just a bit more complicated.
- If “X” is BBY, then 3653 - X
- If your answer is a positive, you are in ATC. If your answer is a negative, you are BTC.
- If “X” is ABY, then 3653 + X
For examples we will take the following two events:
- 303 BTC - The Jedi Civil War (KotOR)
- To turn 303 BTC into ___ BBY, use the “X + 3653 =” equation; if X = 303, 303 + 3653 = 3656
- 303 BTC = 3656 BBY
- 32 BBY - The Blockade of Naboo (The Phantom Menace)
- To turn 32 BBY into ___ ATC, use the “3653 - X” equation; if X = 32, 3653 - 32 = 3621. Because 3621 is positive, you are after the Treaty
- 32 BBY = 3621 ATC
And that is how you convert dates between the Old Republic and Rebellion Eras. *Special thanks to askshivanulegacy on Tumblr for helping check the math.*