In addition to Andrrew's specialized Guide, I wanted to create a more general guide because I saw several posts in which people described difficulties especially regarding stability. Since I very rarely have such problems I wanted to share my experiences. All of my advice can of course be transferred to the lower difficulty settings. Speaking of difficulty settings: This game is balanced to be played on Monarch and I strongly advise you to play on a level that suites you. Because - in my opinion - this game invites you rather to roleplay as the prince of your nation than to seek a challenge on the highest difficulty. But if you do, here are my tipps for you: 1. Basics Don't work unimproved tiles. Workers are very cheep. Don't be too lazy to build them when you need them. Learn to use binary research: Accumulate money on 0% research. Spend your money on 100% research. Switch according to your building queues: Are your cities building science buildings? Save your money until they are finished. And vice versa. Plan ahead your city grid. Use your starting settlers to settle high prodution cities or cities that will benefit you otherwise (like high commerce or happiness ressources). Grow your starting cities to their happy cap (or until they can't work anymore useful tiles) then use them to build more settlers. 2. Economy In comparison to Vanilla BTS, economy works a little different in RFCE. Your strongest economy building will be the market for a long time (note: this does not apply to the Muslim civs) - not the library which doesn't even exist in this mod. The market supplies you with a Trade Route and boosts your economy when your research slider is at 0%. Regarding Trade Routes: Don't neglect them. Actively try to contact your most important trading partners: Constantinople, Rome and civs with access to islands (England, Genua, Venice, ...). Other early economic buildings are the monasteries. They are weaker than the market, though. The most important economic building in the mid game is the wharf - an incredible building that gives you a flat bonus for every river tile - followed by banks, universities and later on seminaries. If you have the corresponding ressources, warehouses can be very powerful, too. Building Economy or Research has been significantly nerfed in this mod. So, it's almost always better to build regular buildings, in my opinion. You will still have to think about whether you need weavers or inns in all of your cities (you probably don't). 3. Research Research is another thing that is slightly different from the Vanilla game. Not only will technologies get more expensive the more your Empire grows, but they will also be harder to reach the more ahead of your time you will be (shown ingame as a percentage modifier on your research bar). This means it will be harder or next to impossible to beeline techs that would be anachronistic. That in turn means that you have to match your technogical aims with the discounts and penalties of your era. If you are a backwards civ, you can of course use this system to your advantage and catch up more easily to your competitors. 4. Great People This brings me directly to the issue of Great People. The research system mentioned above translates into a massive devaluation of Great Scientists which is aggravated by them not being able to build academies (or at least until the very late game). They are next to worthless as a result. Great Spies suffer from the same problem, as techs that you could steal will also be very expensive. The other spy tasks are unchanged from the Vanilla game. I read in some thread that infiltrating the pope and stealing from him can be very valuable. To attain certain Great People you will have to check each city each turn which specialists they are working. Building Wonders with Great Engineers is my favourite because on Emperor the race to certain wonders can be tight. Slower research can be compensated by a Great Engineer and high production. Sending a Great Merchant to Constantinople or Rome is always a good idea. Great Priests excel mostly at obtaining Faith Points when playing as a smaller civ. And last but not least, sacrificing Great People to get a Golden Age is worthwile especially if you want to change civics. 5. Stability This stickied guide tells you all you need to know: Try to found cities in your core provinces. Avoid unhappy cities like the pest. Also avoid unhealthy cities if you can. That means that you will have to trade for ressources. Build stability buildings. Don't let barbarians or enemies pillage your improvements. Don't let them take your cities. That means you have to be prepared for invasions or crusades. Be in a stable civic combination. (Feudalistic combo is the most stable.) Also always be in Militarism (switch right after you spawn). You will most certainly only get stability hits when you want to expand, that's why Militarism is the go to civic in the Expansion tab. Switching out of it is not worth the anarchy. Also don't be in Anarchy, when you can avoid it. (Golden Ages or Palacio del Pena prevent that.) If you want to expand, be stable first (+20 minimum). Remember, this is a medieval mod. Don't blitzkrieg your neighbour. Take one city after the other. If you reach "shaky" stability levels it's maybe time to stop to recover. 6. Military Defending There are two obvious threats to you: barbarians and your neighbours. Let's address the neighbours, first. It will probably happen to you (at the latest when reaching your second UHV condition) that a neighbour will declare war on you. Oddly, the AI rarely follows its declaration with actual troups to threaten you. I've yet to see a stack of doom entering my borders. Thus, you often don't have to worry about the aggression. It's sufficient to have walls and two units in each city that you can move to a possible point of a hostile entry. I often go with a combination of spears and bows. Barbarians are more dangerous. Especially on Emperor level, the early barb pressure can seriously threaten certain civs (looking at you, Bulgaria). Since you often don't have time to build up against these forces you often will have to save some of your starting units to stay and defend. You can use the experience you gain to promote axes or spears to Guerilla or Woodsman to also defend valuable ressources. Don't forget to use light cavarly to attack or flank the barbarians and finish them off with your slower units. Since they often have 3 movement points you don't have to maintain a vast amount of light cavalry. Against invasions (Mongols, Seldjuks, Crusaders, ...) build castles and have 4+ defenders (8+ for crusades). Remember that crusades can also hit you when you're Byzantium or Cordoba. Attacking In this mod you won't need a large stack of doom to invade an enemy. Usually, 4-5 siege, some knights and some defensive units are sufficient. For faster progress bring a medic. For big civs like HRE you will probably need more, though. Pillaging One of the most improtant things to do when you start in the early Middle Ages is to pillage your surroundings. There are villages and town improvements all over the map. Find them and destroy the ones you won't need (and you probably won't). The spoils will finance your early research and the spawning spearmen can train your axes/swords. Cottages that are too far away from your slower units are to be pillaged by your light cavalry. Just take care to not lose your units in the process and be warned that the increased barbarian activity will very likely cause damage to their neighbouring cities (which of course can be beneficial to you). 7. The Plague You can do nothing to prevent the plague from hitting you. All you can do is keeping your cities as healthy as possible, keep a Medic I unit in each city to save your units and pull your workers into your cities to save them from dying. I'm not sure whether this bug is still around but taking a city while in a plague resets the plague counter and you could have the plague twice in your cities. So put your wars on hold when the plague hits you. Also remember that the plague can shrink your cottages making them even more inferior to other improvements. 8. Religions Don't underestimate the value of faith points. While they are pretty straight forward for Orthodoxy, Islam and Protestantism, they are also very valuable for the Catholic. A lot of faith points will enable you to lead a crusade, will make it wore likely that knightly orders will spread to you and most of all they make gifts from the pope more frequent. These gifts can be money, free churches and monasteries and free techs. 9. Victories Think about which victory conditions you want to meet. The UHV will almost always be the easiest. But will it be the fastest? Why not try to get a culture victory with the Scotsmen? Or try a Domination Victory? For that, vassals will be useful. But the more vassals you get the harder it gets to vassalise other civs. This gets noticable after the third or fourth vassal. Because of that you will have to choose which enemies to vassalise and which to eliminate. For example, if you're invading Great Britain and don't choose to keep it, don't vassalise both England and Scotland. Keep England and gift them your conquered British cities. 10. If at first you don't succeed... ... then dust yourself off and try again. Check out what went wrong this time: production too low, not teching fast enough, etc. Improve on that in your next try. That is all I think. Questions and critism are very welcome.