Mongolia is one of the easiest civs to do domination with, especially on Pangaea Mongols dont have an unique combat unit(UU), but their unique ability(UA) gives the skimisher line (mounted ranged units) +2 movement and ignores zone of control(ZoC), this may not seem like much but it is actually amazing because it basically means your units can come and go as they please and nobody can stop you, not even ZoC trapping will work on you, basically, when you are on the offensive(and you should be often as mongols) your units shouldn't ever die, as you just shoot the fallback without ever taking damage, 6 moves allows much flexibility even in rough terrain. Also, your UA works all the way up to helicopters where as other civs UU's will eventually become obsolete. your UA also allows you to annex city states if you can levy heavy tribute, whilst also gaining golden age points(GAP) and culture from it which comes really handy early game The first tech you should research is animal husbandry which reveals HORSES!! they are KEY to your conquest, grab as many of them as you can. if there are horses outside your capital then you should research pottery and grab the horses asap, if the horses are within nearby city states then get trapping and bronze working cos it's time for some bullying, if there are no horses within sight then explore like a madman to find those horses. If there are really no horses, which would be very rare then you might want to restart and check strategic balance. So if all went well and you got yourself some horses and got yourself the authority opener use all your horses on chariot archers and start hunting barbs, with 6 moves you will be the first to the camps. always work in teams of 2 chariots as you cannot kill the defender and take a camp in the same turn with 1 chariot. Get your culture rolling by barb hunting and once you earn enough to get dominance start beating on nearby city states with the best resources folr science (the order is horses-> lux -> cows/sheep -> others) kill all their units for science/culture. If there are a few city states around you dont really need to build that many settlers since city states have at least 1 luxury and are usually in good locations. whilst you are kill cs units, you might want to grab the is statue of Zeus, which is the only wonder you really want. once a city state's units are dead, put your army next to it and declare peace->ask tribute->annex. This gets easier with skimishers as you can grind down the city states hp and kill the garrison, which is hard to do with chariots and spearman. So beeline to trade and mathematics since you really need gold and skirmishers to actually take the cities once you have skirmishers, their move after shoot ability allows you to grind down the city states hp without receiving any damage. you can grind down the hp for exp if you want, depending on circumstance. Use shoot and fallback tactic and stay out of range of the city, which is only 1 in the early game. when you had enough annex the city state. Keep doing the same thing and aim to get for physics quickly for heavy skimishers, which rapes all classic era units. for your 2nd policy tree if you have a religion then pick piety, statecraft is not useful as you are killing city states rather than allying them, and aesthetics isnt that useful either since you wont be going for a culture victory, so if you dont have a religion progress is actually a good pick since the % bonus on buildings scales, with both progress and authority your new and conquered cities can get their buildings up in crazy speed. Hopefully now you have killed a couple of city states and one of two major civs, dont forget to bring along a horseman/knight to take AI cities, which you didnt need to annex city states. your skimishers should be stacking tons of exp since they never die and once they get to lvl5 for the extra range then lvl6 for the double attack your conquest becomes much easier. Next beeline to metallurgy for curassiers and if the AI is not in late industrial/early mordern it's pretty much gg. with 8-10 full upgraded curassiers cities will fall in 1 or 2 turns without anything they can do about it, even awkard cities surronded by mountains with only 1 hex to attack with is no problem because your units can take position-> shoot->clear position for the next guy to shoot, kinda reminds me of a certain genre of videos where a bunch of guys take their turns to shoot (some even twice ) The 3rd tree dont really matter which you pick, personally the times I played the game is pretty much over by that time, so just do whatever you fancy and continue your conquest and kill everybody!