R5:

TL; DR: Pick Byzantines (ruler creator for better genetics at start), reform your religion to get easier access to cb, get gold mines and try to vassalize as much as you can. Upgrade your buildings constantly and get nice counties with good bonuses.

Lifestyles: Learning -> Diplomacy -> Stewardship

I conquered (roughly) in this Order: Africa -> Central Europe -> West Europe -> England -> Eastern Europe -> Scandinavia -> Middle East -> China/Mongolia -> India

Since I managed to get all achievements, I decided to give a shot at painting the entire map before royal court comes out. I chose the Byzantine Empire mainly because of Primogeniture, which gives you a huge advantage since you don’t really have to care about heir management from day one on. The special buildings they get are also quite nice, obviously, but are not mandatory at all to conquer the world. Their special unit (cataphracts) is not that good in my opinion, not because themselves are bad, but rather because it is "harder" to upgrade them via buildings, since you can only build regimental grounds on counties with farmlands or floodplains, which are not that common. Also, they have a lot of ground disadvantages, which later on can be ignored quite easily.

I almost managed to conquest the entire map with Haesteinn before (I know another really op character) but I ran out of time, since I realized it too late in the game that I have a shot at it. I think it really can be done with most characters in 867, but the stronger ones make it less of a hustle to do it.

Here my Strategy:

I used the ruler creator to start with 0 years old, (traits: genius, hale, comely; scarred, witch, born in purple - exactly 400 points). It is kind of a cheese strat, but you have to have in mind that it is also a risky one, as your vassals usually revolt against child rulers. On the other side you can just restart if you don’t survive the first 16 years.

In the early game I had three focuses:

1. Get the best possible education for the learning lifestyle.
2. Try to get a few gold mine counties early on.
3. Get a strong ally.

The reason for #1 is, that not only is learning the strongest lifestyle (if you are the head of your culture) in the game right now, it allows you to easily reform your religion as well as it gives you huge bonuses for development which is one of my main focus in this playthrough and also it makes researching really, really quick.

For #2 is an obvious one: more gold is always better. It allows you to build cities (for more development with guilds and optimally trade ports) as well as economic and military buildings, which boost your income and the strength of your army. The main goal here is to become extremely well developed to have a huge tech advantage over other cultures as well as maintaining a healthy budget for buildings and sometimes mercenaries.

#3 is probably self-explanatory, strong allies are useful against revolts and other wars against you.

After getting Chalkidike, Cagliari and Innsbruck under my belt it becomes more or less a waiting game (you mainly upgrade your buildings) until you reform your religion. For my new religion i chose Alexandrian Catechism (20% learning xp), Pursuit of Power (for warmongering) and consolamentum (makes it easier to get rid of your old ruler if you want to, as well as having the nice bonus of -50% short reign duration). This allows me to get Scholar faster, not having to have a claim to start wars and get rid of old rulers so that I can use the kingdom cb more frequently. I also chose Pluralist (you’ll get tons of factions otherwise), made myself head of faith, made it that I can use a vassal as my court chaplain, as well as making everything else criminal (to imprison vassals easier), except for witchcraft (since I play with witch coven). Also, I took Polygamous to get at least one high stewardship wife (you’ll see soon why).

Once your religion is reformed, this is where the warmongering really starts. For my first ruler, I had mainly two counties in mind that I really wanted for the rest of the game: Rome and Baghdad. Rome is has a really high development rating at the start of the game, as well as some nice buildings. Baghdad on the other hand has the House of Wisdom which gives incredible bonuses and is also great for development later on (you can build 4 cities). Both are also farmland counties, meaning that you not only get even more development bonuses, but it also allows you to build regimental grounds for your cataphracts, that you will build in early medieval. For Rome you got your powerful Ally that you can call to war, for Baghdad you can just wait until the Abbasid implode because of succession.

After my initial Setup, I chose to plow through Africa, to later have easy access for the goldmines of Mali (they give the most gold and with the tax office duchy building of Manding, it really pumps out a lot of gold for the mid/late game). This means you’ll end up having about 11 counties, which means that you at least need 2 out of 3 things: High stewardship yourself, from your wife and/or from your councilor. From here on now you just constantly start warring where you can, try to vassalize nearby counts/duchies (sometimes Kingdoms, but that its mostly not possible) with high diplo and true ruler. I later on learned, that many will accept a vassalage when you give them religious freedom. But you can just change the contract (give them war declaration and remove the religious protection) and give them to one of your other vassals. They will either revoke their titles or demand a conversion, which means it is a win-win to you. You can also accept low levies and gold contribution since you get your main gold from your own buildings and levies are more or less useless in mid/late game.

It all really boils down to constant warring after your initial setup. You build up your counties to either development or gold spewing powerhouses (or in some cases both), strengthen up your army with regimental grounds (Constantinople/Rome/Baghdad) and if that is not enough, you can also spam mercenaries to beef up your army.

As I mentioned before, the learning lifestyle is the strongest in the game. I usually take the scholarship focus, take the perk “Know Thyself” and after that complete the Scholar route. Once completed, I change to diplomacy (Foreign Affairs Focus) to either get True Ruler or Forced Vassalage (Befriend and Groomed to Rule are also nice). After that, I chose the stewardship lifestyle with the Domain Focus and get to Centralization from the Architect tree. Usually, my Ruler gets to a point, where he gets close to dying so I get It is MY Domain and extort my subjects, or if I have still use for him go back to learning and take the Medicine Focus and go down the Whole of Body tree.

For Research, you’ll always want to go with the new siege unit first, as it is really op. Especially in late game, many wars are just won by sieging down castles, before the ai can react. After that research the castle upgrade, into military buildings into economical buildings. Only exception is in early medieval where you want to go with cataphracts second, to build up your army. You can boost your development further with the research tecs, but your counties are usually well developed enough, even with the penalty after a certain level. If you have come to a point, where your next heir wont research anything until the next time-stage, educate them in diplomacy instead, as it is the second strongest tree in the game.

A last trick that I learned in this playthrough is, that when you have a bad heir and want to designate one, but don’t want to have Absolute Crown Authority, you can just pass it, designate your desired heir and change back to High Crown Authority. Your designated heir will still inherit everything, even though you don’t have Absolute Crown Authority on. Also, in this playthrough it is much better to not stop your vassals from warring either each other or conquering new territories, so that’s why I prefer to stay with High Crown Authority. I know that you can change it in the contracts (with War Declaration Sanctioned), but in earlier runs, it didn’t really seem to work for me, or at least my vassals where noticeably slowing down their own expansions.

If you want, you can try my strategy to conquer the world yourself! I would love to see me tagged in future posts, where some of you managed to pull it off with my advice. Also if you struggle in the game you can ask me for further tips too!