To get this achievement you need to beat the game once as each of the 18 leaders in the base game. The leaders added by the DLC and expansions are
not needed for this achievement. There are additional achievements associated with each of these leaders so you will get the following achievements while going for this one:
You can get these naturally over time but to get them all quickly set up the games like so:
Map Type: Great Plains
Map Size: Duel
Difficulty: Settler
Game Pace: Quick
Game Era: Ancient
Victory condition: Domination
City-States: 0
Other: No barbarians
Opponent: Any but if you have Brave New World go with Enrico Dondalo of Venice since he can't settle any new cities making things slightly faster sometimes.
For each game do the following:
1. At the start of the game you will start on either the West or East side of the map. Send your warrior/scout along the northern or southern edge of the map in that direction and recruit another one to go the opposite side (north or south).
2. Research Archery, Construction, and Mathematics as soon as possible. Add any other techs that you like. Engineering can save a turn or two of movement with bridges.
3. Build a monument and then barracks. Bonus building are Statue of Zeus for city attack bonus and Temple of Artemis for growth bonus and ranged unit production boost. Also building temples counts towards
.
4. For policies do
Honor -> Warrior Code. Then if your scouts have not gotten a worker or settler from ruins yet
Liberty -> Republic -> Collective Rule or
Libery -> Citizenship. Otherwise, continue filling up the Honor tree.
5. As soon as you have a settler send him to settle close to the other civ and have your worker build a road from your capital to the new city and then to the border of the other civ and then around the border if you have time.
6. As soon as you have a barracks build two melee units (doesn't really matter which, I use spearmen or swordsmen if I've discovered iron nearby), an archer, and one or two catapults. Start moving them into position around the capital of the other civ and start building Terracota Army. By the time they get into position you should have TA finished and almost double your army size in case you need reserves somehow (in my Alexander run Enrico somehow already had three spearmen and an archer by the time I got there).
7. Declare war and move in with your melee units closest and ranged/siege units one tile behind. Don't have your melee units attack until the city is ravaged (minimal/no health); just have them fortify. About ~75% of the time the enemy will focus on them and leave your siege engines alone. Once the city is worn down (2-3 turns), have a melee unit attack it and game over!
Using this method you should be able to finish a game in about 15 minutes, usually around 600 B.C.