Social strategy (Civ5)

==Introduction==
This article discusses general strategies for developing social policies in Civilization V. It was written for the Brave New World expansion after the Fall 2013 patch, and because of the frequent and sometimes quite sweeping changes in the Social Policies, it may not be applicable to earlier versions of the game.
Social Policies represent a crucial part of the abilities of an empire - their bonuses are extremely useful throughout the game. Empires which manage to adopt more Policies for a given number of turns may easily emerge ahead of the competition, provided the Policies are well-chosen and match the player's chosen civilization and victory path. Never underestimate a rival who focuses on social, rather than military or scientific, development.
==Acquiring Social Policies==
Social Policies are "bought" via accumulating . Each time you acquire a certain minimum amount of this yield (determined by the number of Policies you already adopted and the number of cities in your empire), you're prompted to spend it on either unlocking a Social Policy tree, or adopting a Policy within one you've already unlocked. Note that most trees can't be unlocked in the beginning of the game - they become available only as you progress to later eras. Also, all high-level Policies within each tree require adopting other, lower level Policies first - the design of the tree will let you know the exact relation.
Note also that you can't "skip" adopting a Policy (unless you enabled policy saving before starting a game) - the game simply won't let you end your turn. This fact also merits some strategic decisions, mainly in the early game when few trees are unlocked. If, for example, you've completed your initial Social tree and want to adopt next one of the higher level trees (e.g., Patronage or Commerce), you must make sure you've reached the era unlocking that tree before acquiring enough for your next Policy! Else you will be forced to spend a Policy for something that doesn't really fit your strategy. So, plan your scientific development well - this is what determines when you enter later eras.
Each time you acquire a Social Policy, the amount of needed to get the next one increases. The exact values seem to vary according to the number of Policies you've already acquired (for example the initial progression is almost geometric, but then after 6-7 Policies it turns percentual), and according to the number of cities belonging to your empire (excluding Puppet cities). The fewer cities you have, the faster you'll be able to adopt new Policies.
Once you unlock and adopt an Ideology, you will be able to spend your accumulated on acquiring Ideological Tenets as well as Social Policies. You will have to decide then whether you want to develop your Ideology, or continue developing Social Policies.
Some game events allow you to acquire a free Policy or Tenet - this won't affect your accumulated , and won't raise the amount needed for your next "normal" Policy/Tenet.
As a general rule, the more you manage to produce with fewer cities, the faster you'll progress socially (meaning that you'll be able to adopt many Policies). Also, keep in mind that in the final phase of the game you'll have to split your social progress with your ideological progress, so think very carefully about what will benefit your empire more at that point and act accordingly. Usually, Ideological Tenets are more powerful than Social Policies, but sometimes there are exceptions, and some trees are simply too important for specific victory paths to be left hanging.
==General Strategy==
Choosing the right Policies for your civilization and chosen victory path is crucial for success in the game. It can mean the difference between having a set of bonuses which supports your playstyle and helps you advance quicker, and having bonuses which are of almost no use to you and will cause you to lag behind the competition.
Because of the great variety of strategies and means to achieve victory in the game, there are so many possibilities when using Social Policies that it will be impossible to list them all here. Still, there are some things you should consider for the start of the game:
* You will be able to adopt policies relatively quickly in the first 100 turns or so. You will be able to finish one of the starting four trees completely, or get well under way (but not complete!) two of them. So, one of the greatest choices you will face in the early game is whether to complete one Social tree and get its full benefits, or use the two-sided benefits of two different trees, but take longer to reach their final Policies and bonuses. Both approaches have their merits, but you should be aware that the most powerful Policies of every tree are usually unlocked last.
* It is nearly always better to complete a tree (unlock it and adopt all 5 Policies in it) before moving to the next one, because this way you get the special "finisher" bonus of the tree as well. And since you won't have nearly enough to adopt more than 3-4 trees plus an Ideology throughout the game, you should carefully choose which trees to pursue.
* You should also be aware that the first four trees (Tradition, Liberty, Honor, and Piety) have bonuses well suited for the beginning of the game, but some of them become quite useless in the later game...or rather, there are other, much more profitable ways to spend your at that time. For example, it's not smart to start developing Tradition in the Modern Era, when you can instead develop your newly-chosen Ideology.These starting Social trees are very different from each other, with distinct effects and aims. Form a strategy for your early game right from the start, and apply it to your Social choices! For example, if you decide to expand early, adopt Liberty. On the other hand, Tradition could nicely boost your and give you free buildings in your first 4 cities - choose that if you're not in a particular hurry to occupy territory. If you want to fight aggressively, adopt Honor, even if you don't intend to pursue a domination victory - there's always fighting involved, especially on higher difficulty levels, you'll rarely finish a game without having to wipe out at least one other player. And, if you want to use the full benefits of Religion, adopt Piety - it will help you establish a Religion faster, and start reaping its benefits early.
* The later trees (from Patronage on) are meant to be used in later eras, and you should pass to them as soon as you've finished your starting tree (or one of them, if you chose to develop two at the same time). Their Policies often have more powerful effects than the first four trees, and will be more useful than if you try completing early-game trees. So, for example, don't insist on developing a third of the starting four trees once you can choose from one of the higher-level Policies. Choose your next tree according to the way you're developing your empire.
* Each policy tree is designed with a particular game domain in view, and you should consider adopting it if you decide to develop that domain. For example, if you're building a maritime empire, adopt Exploration; if you rely on for progress, develop Commerce; if you want City-State allies, develop Patronage.
==Tradition==
Tradition enhances general  growth (especially in the ) and speeds up development in your first four cities. It's best for empires which will depend on having a large but few cities, and probably the best one to start with if you don't want to expand quickly. It is also good for any civilization which is strongly centralized (like the Romans), because it gives nice bonuses such as faster growth, increased generation, and decreased for citizens in the . It is also considered the most powerful of the starting four by most of the Civilization Reddit players.
Historically, this tree represents aristocratic and feudal traditions, with their centralization, class distinctions, and a tendency to favor a closed, non-expansionist system.
Its opening bonus adds 3 to your , and reduces the amount of accumulated needed for conquering each successive tile in every city. That means that your borders will be growing really fast, all the way until the end of the game! Add to that the free Monument from Legalism, and your first four cities will grow their borders for a fraction of the time normally required! The Wonder unlocked, the Hanging Gardens, is also oriented toward growth.
If you want to have large cities early on, you'll want to adopt Oligarchy first and then work your way through the branches it unlocks - their effects are more oriented towards large cities, rather than towards the beginning of the game.
*Oligarchy - It's a good idea to adopt this Policy as soon as you start expanding your empire (especially since it's a prerequisite for three of the higher-level Policies). It helps to keep your accounts in check, as well as defend your cities. To make use of it, keep a unit in each city you have at all times when not at war.
*Legalism - It gives you a free culture building in your first 4 cities, which in most cases means a free Monument. Since you should be developing Tradition in the beginning of the game, the free Monument opens up your initial building order, allowing you to concentrate on other things instead of a Monument. For example, you could build several Warriors, or a Worker early on! Bottom line, if you plan on adopting Tradition, don't waste time building a Monument!
*Landed Elite - The sooner you can adopt this Policy, the better. The and growth bonuses in the can be priceless in the early game, when every counts.
*Monarchy - This Policy becomes more useful the larger your grows, giving you and reducing . Adopt it late to get a nice boost.
However, if you plan on building a Wonder early on, the first Policy you adopt should be...
*Aristocracy - Its 15% bonus towards building Wonders will help you throughout the game, but it may mean the difference between success and failure in the first 100 turns. Also, the other bonus helps maintain further in the game.
The completion bonus of this tree gives you another growth boost in your first 4 cities, and also provide a free Aqueduct in them. For maximum effect, try to obtain it before turn 150, and also try founding four cities before, or at least right after you complete the tree. Also, you get to purchase Great Engineers with .
==Liberty==
Liberty helps quicken initial expansion, by helping the establishment of cities and the building of buildings and improvements right from the start. Further on, it also helps larger empires with more cities thanks to the many per-city bonuses. One of its best features is the free units provided (a Worker and a Settler), which will help your early development immensely. Another important highlight is the faster improvement building, which allows you to develop the land quicker and with fewer Workers.
Conceptually, Liberty represents the power of early democracy as means of establishing expansionist countries. In these, society is based on "people's rule" where everyone is "equal" (as opposed to the class system of aristocracy) and has the right to be represented and have a voice in the running of the country.
The tree's unlock bonus provides +1 generation to all cities, including newly founded ones. That means that their borders will grow (albeit slowly) even before you construct cultural buildings in them, which is important. Also, the Pyramids give you more free Workers while additionally boosting improvement building speed.
You have to choose the first Policies you want to adopt carefully. There are two options: going for a free Settler early (which means adopting Republic, then Collective Rule), or going for a free Worker first. But having a Worker won't help you a lot unless you have the technologies needed for improvements, so if you're going slow in tech development (or if you were lucky to get early), go with the first option. It won't do you much good to have a Worker if all you can build is Farms, and you can always get it as the second Policy you adopt instead of Collective Rule.
*Republic - One of the possible first choices for a Policy, it allows you to build things faster in your cities, especially buildings. A very nice Policy to get you started on making your cities more useful. And it opens up the path to getting that free Settler. Take it first if the conditions aren't right for the other choice, or if you plan an early expansion.
*Citizenship - The second choice for a starting Policy, it will give you a free Worker and increase the speed with which improvements are built, which is very nice. It combines nicely with the bonus from the Pyramids to allow you to build lots of terrain improvements with few Workers. Thanks to this combo, it may be possible to make it all the way to the late game with only three Workers. Choose it first if you have already the techs to access most resources near your - the resulting boost in development could be great! Be mindful, however, that a Barbarian invading your defenseless city may strand your new Worker and make it practically useless!
Citizenship also unlocks the other two high-level Policies:
*Meritocracy - This Policy enhances , mainly based on the number of cities connected to the . Adopt it only after you've started connecting your empire with Roads, focusing on other Policies until then.
*Representation - This Policy reduces the penalty for having lots of cities in your empire, so adopt it quickly - it will immediately translate to faster Social progression. It will also start a , or extend the current one, which is always nice.
*Collective Rule - This Policy gives you a free Settler and considerably speeds up the production of Settlers in the , allowing your continued fast expansion. To make best use of it, you should always construct Settlers in your after adopting it. If you are playing as Venice, you will receive a Merchant of Venice (which will affect how long it takes to receive your next Merchant of Venice).
The completion bonus for Liberty - a free Great Person of your choice - is a bit anticlimactic. While this bonus could be very nice in the first 100 turns, its value diminishes later on (when it gets increasingly easy to get Great People), so look to complete the tree early on. The Person you choose should help your empire overcome its weakness in this particular moment - some good choices include a Great Scientist for improved tech development, or a Great Engineer for a boost in a major city's . And do not use its one-time boost ability - this is wasteful in the beginning of the game! Also, it might be tempting to choose a Person which is related to a City-State quest, but you should do this only if it will also help your empire's development at that moment. A Great Artist, for example, will rarely be useful in the first 100 turns of a game.
Last, but not least, you can use a Great Engineer to complete an important Wonder instantly, getting Petra, Machu Picchu, or the Borobudur as early as 2000 BC. This is the only instant-ability use recommended, and only if the particular Wonder you choose is really important for your future development; otherwise, it's not worth it.
==Honor==
Honor enhances your combat abilities throughout the game, especially in the early game and against Barbarians. It is strongly recommended for those attempting a domination victory (who should take it as first and main tree), but partially it is also good for everyone that desires a little combat boost. It also rewards an aggressive playstyle throughout the game.
Conceptually, Honor represents warrior societies such as Japan or Sparta, where being a warrior confers a high social status, but at the same time entails following certain rules in life instead of simply bullying everyone around. In short, it is not only a means towards defending your lands (or conquering foreign lands).
The unlock bonus is one of the most sweeping bonuses in the early game: +33% against Barbarians for all units, earns for each Barbarian killed (the exact amount varies according to the unit destroyed), and reveals newly spawned encampments in all revealed territories. This "package" is often worth it spending one Social Policy, even if you don't intent to be particularly warlike in the game, because it helps you defeat easier the early Barbarian rushes, clear Encampments for City-State quests and also speeds up your Social development. You can use this unlock bonus in combination with all other opening gambits to help your early game.
There are two distinct paths through the tree:
# Warrior Code -> Military Tradition is purely combat-oriented. Follow this path if you intend to start fighting right away. 
# Discipline -> Military Caste -> Professional Army has a more long-term benefit, which will also improve your and . Follow this path if you're in no particular hurry to attack.
The Wonder unlocked, the Statue of Zeus, isn't that exciting unless you really intend to pursue a domination victory, as it gives a bonus when attacking cities.
*Warrior Code - This basic Policy speeds up creation of units in all cities and Great Generals and even gives you a free General. Take it early on only if you intend on rushing a neighbor, otherwise prefer the other tree option.
*Discipline - This Policy adds a permanent ability to all your Land units, increasing their Combat Strength when they're in formation. Incredibly useful for big battles, and also opens up the path to even more useful high-level Policies:
*Military Caste - This Policy gives 1  and 2  to each city with a garrison. It combines well with a large army, helping your empire's Happiness and early Culture growth, and your Border growth at the same time. After adopting it, try keeping a Unit in each city when not at war.
*Professional Army - This high-end Policy reduces the cost for upgrading Units and speeds up construction of Military training buildings - very useful for a war-like civilization, especially when you have a large army in constant need of upgrades. Also a must have for early unique units that keep their special abilities after upgrading, like the Jaguar.
*Military Tradition - The follow-up of Warrior Code, thanks to it units gain XP 50% faster (that is, when they should gain 2 XP for something, they gain 3 instead, etc.). Try to adopt it right before your first big offensive and watch your Units pile up Promotions like crazy!
The end bonus of the tree gives you for each enemy unit killed, including Barbarians. The more aggressive your civilization is, the more useful this becomes, and it's a great boon when pursuing a domination victory, where it is often able to replace the lost from not being able to establish trade routes due to your being at war with most of your neighbors. So in this case, try completing the tree as early as possible, before or during your first big offensive. Also, you'll be able to purchase Great Generals with from the Industrial Era on.
==Piety==
Piety was initially the -oriented tree, but in the expansions it was gradually shifted towards Religion and production. In Brave New World the tree becomes available right from the start (before it was only unlockable in the Classical Era), which makes it a viable choice for a starting Social Policy tree. Choose it so if your civilization has features related to Religion, and if you plan on using Religion as a serious weapon in the game. Also, consider developing it parallel with another starting Social tree, because its bonuses are very specifically religion-oriented. The problem is that you don't have a Religion right from the start of the game, so Policies like Religious Tolerance and Reformation will be completely useless until you either develop one, or some neighbor spreads their religion to your cities. In fact, of all Policies in this tree only the opening bonus and Organized Religion are applicable right away (assuming you built a Shrine quickly in your cities) - the others become useful only towards the middle game.
So, while enhancing your Religion, Policies from the Piety tree might actually hinder your development otherwise (because you're not getting other, more useful bonuses). Still, it's all a matter of ability - Religion is in itself a system of bonuses, and developing it early not only lets you use all these bonuses, but also lets you choose from a greater pool of available Beliefs and gives you a greater chance to spread it to your neighbors. If used right, this tree combined with well-chosen Beliefs will boost your development and establish you as a regional power even if you've done nothing else of note until that moment.
Conceptually, it represents theocratic societies centered on Religion and implementing their social systems around and via Religion (e.g. implementing laws based on religious beliefs). Examples here include some kingdoms in Medieval Europe, and many Islamic countries ruled by religious law.
Its opening bonus lets you build Shrines and Temples twice as fast, which is really helpful for jump-starting your production. It also unlocks the Great Mosque of Djenne Wonder, which is quite possibly the most useful of the religious Wonders because of the extra "Spread Religion" ability it confers to all Missionaries and Prophets born in that city. As a result, you'll have more to spend and greater ability to spread your Religion.
*Organized Religion - Adds +1 for Shrines and Temples. Simple and useful. Also, it's required for developing further.
*Mandate of Heaven - Reduces price of all purchases by 20%. Also very useful and practical throughout the game. Of course, it's useless if you can't purchase anything yet, so focus on developing the other side of the tree and only adopt this AFTER you found a Religion. Note that late-game purchases of Great People (including initial spawning of Great Prophets) are not affected by this Policy!
*Theocracy - This Policy lets you earn via religious institutions, by adding a +25% bonus to Temples and +3 production to Holy Sites. A piece of Jesus' robe anyone? However, keep in mind that the Policy is useless until you've actually built some Temples.
*Religious Tolerance - A very interesting Policy, it lets your cities also use the Pantheon Belief bonus of the SECOND most popular religion in them. Of course, for the bonus to activate, you need to have at least two religions in cities, so don't be too keen on using Inquisitors (who will purge all religions other than theirs from a city).
*Reformation - The high-level Policy of the tree, it lets you add a special Reformation belief to your Religion (check the possible choices here). This Policy alone is often worth it developing the whole tree, because there are some really awesome bonuses to choose from! However, you can only choose it after developing a Religion (if you get late with that, and adopt the Policy before creating a Religion, you will get to choose the bonus at the time of creation of the new Religion). This shouldn't be a problem normally, since earlier Policies boost your ability to generate , thus allowing you to spawn a Prophet and found a Religion much sooner than normal.
The completion bonus of the tree adds +3 production to Holy Sites, which now produce a total of 6 , 3 and 3 , besides the natural terrain yield. Needless to say, Holy Sites all of a sudden become one of the most useful Great Person improvements in the game! So, keeping that in mind, you should use your Great Prophets exclusively for making Holy Sites, even before you complete the tree. The second effect is a free Prophet, which can be extremely useful if you time it right. You can use this Prophet to Enhance your Religion, while spending the you've accumulated after founding it on a Missionary to spread it, or a religious building. If, for some reason, you've already enhanced your religion, make a Holy Site to start reaping its many benefits!
==Patronage==
Patronage is the tree for those preferring to form alliances with City-States, and a must for those attempting a diplomatic victory. However, its main purpose - improving your ability to influence City-States - combines well with all gameplay styles and empire types, so even a partially-completed Patronage tree can help supplement other strategies. Its first Policies, for example, are useful throughout the game and may be well worth the spent for a player who knows how to make use of the bonuses of City-States. Also, keep in mind that Patronage is more useful the more City-State allies you have - try to focus on acquiring more if you develop the tree.
It becomes available in the Classical Era, so it should be your second or even third Social Policy tree.
Conceptually, Patronage represents the diplomatically-oriented society, which likes maintaining close relations with all other political entities and engages in all sorts of peaceful interchange with them (rather than invasion interchange).
The unlock bonus slows down decay of City-State by 25% (or speeds up recovery from negative ), so take it as soon as you can - it will ensure you keep Friends and Allies longer without having to do anything. The Wonder unlocked is the Forbidden Palace, a key Wonder for Diplomatic victory and a good way to keep in your empire.
*Philanthropy - gifts to City-states produce more . A base Policy, unlocking higher-level ones, but its effect is very nice. Take it ASAP unless you haven't met enough City-States yet or you're having problems producing for gifts, in which cases you might prefer... 
*Consulates - This Policy pushes the resting points with all City-States to +20, making so that you will be very close to being Friends with all City-States without doing anything else. Combine it with other ways to push up resting points, such as Declarations of Protection, and you'll be able to constantly use Friend bonuses with all City-States you're not at war with. Note that, despite the rise in the "neutral influence point" being instantaneous, it will still take some time for the real with each City-State to develop up to the new resting point. On the plus side, this takes place at the same time with all City-States, even the ones you haven't discovered yet.
*Scholasticism - This mid-level Policy grants you  per turn based on 25% of what your City-State Allies earn for themselves. It doesn't total a whole lot per individual City-State, but it really adds up very quickly if you have many allies.
*Cultural Diplomacy - A high-level Policy, and maybe the most powerful Policy in the whole tree; it doubles the amount of Strategic resources you get from City-States and also gives you +2 per each new Luxury you get from them (for a total of +6, as opposed to the normal +4; also note that this only works for Luxuries you can access in no other way). Thanks to this policy, your empire may overcome all sorts of shortages that plague it, and this is also the -boosting Policy of the tree.
*Merchant Confederacy - The second high-level policy isn't that exciting, giving you additional for each Trade route with a City-State. Adopt it last of all Policies to complete the tree.
The final bonus of Patronage is very interesting - all City-State allies give you Great People from time to time. This works much the same way as Militaristic City-States' unit gifts, but the gift rate is lower, and the Great Person gifted - completely random (no relation to the type of City-State giving it). Thanks to this, your empire will be able to use more Great People than others, and if used wisely, they could give you great advantage!  
==Aesthetics==
Aesthetics is a new tree introduced in Brave New World as a replacement for the Culturally-oriented Piety tree. It revolves around the and boosts, and is thus practically required for those attempting a cultural victory, although not very useful for other players. Conceptually, it represents an artistically-oriented society, where Culture and artistic expression is valued much more than normal, even to the point of being heavily sponsored by the state. It becomes available in the Classical Era.
The unlock bonus of Aesthetics gives your Great Artists, Writers and Musicians' generation a 25% boost, so you should adopt it only after you've started producing those. Also, the Uffizi Wonder is unlocked, which is great for development (although its theming bonus is quite tricky to unlock).
The two basic Policies here are both required for progressing further down the tree, so no strategy involved here.
*Cultural Centers - Speeds up construction of culture buildings by 50%. A simple and effective bonus which is always useful.
*Fine Arts - An old Policy from the Piety tree, it adds 50% of your excess to your growth each turn. It can be incredibly useful if your empire is really happy, so look for ways to increase after you adopt this Policy!
*Artistic Genius - Gives you a free Great Artist. It's nice to time its use for when you need a Great Work of Art from a particular era.
*Flourishing of the Arts - This mid-level Policy could be very powerful if you're able to build Wonders in different cities, which all get a boost in their production. Also starts a . Again, try timing it right, if you can (and need to).
*Cultural Exchange - The high-level and most powerful Policy of the tree, it increases by 15% the bonus modifier for Shared Religion, Open Borders and Trade Routes for a total of +40% each! Needless to say, this will boost your touristic influence without you having to do anything, so adopt it ASAP!
The finishing bonus of the tree doubles the theming bonuses of all buildings that have it (i.e., Museums and World Wonders). That is again a great boost to your , becoming more effective the more of these buildings you have, so race towards those special Wonders like the Louvre and Broadway! Also, you get to buy all artistically-oriented Great People with from the Industrial Era on, which is also awesome.
==Commerce==
Commerce was initially designed to include both -boosting and sea-oriented benefits, but in Brave New World it was redesigned to concentrate entirely on Land Trade and output. Conceptually it represents a trade-oriented society, where the state adopts protectionist policies and helps trade in any way they can (even to allowing free mercenary companies to replace regular troops).
The tree is now available in the Medieval Era and can be unlocked quickly by rushing Guilds; however, it offers little in the early game. It is, however, good for all sorts of empires later on, because everyone could use some extra in this game for all sorts of different purposes. The only exception is possibly Domination-oriented empires which won't have many possibilities for trade (being at war with about everyone). Adopt it as a second main tree, or a complimentary third tree right before you start developing your Ideology.
The unlock bonus increases output in the Capital by 25%, which could turn out to be a major boost if your Capital produces lots of Gold (for example, if you have earlier Wonders helping production, like the Colossus and/or lots of Trade Routes from/to it). If this is the case, don't hesitate to unlock the tree as early as you can, because you'll benefit greatly from it. The Wonder unlocked is the Big Ben, which also benefits greatly from  production.
In this tree you can choose two distinct paths: Mercenary Army -> Mercantilism; or Wagon Trains -> Entrepreneurship. The first option has more long-term benefits, including a brand new military unit, while the second offers more immediate benefits for your treasury. Here are the details:
*Wagon Trains - A great basic Policy which lowers maintenance for all Roads and Railroads by 50% and boosts income from Land Trade routes. Always choose it first, unless you really want Mercantilism ASAP.
*Entrepreneurship - This mid-level policy upgrades Great Merchants, first by boosting their spawn rate and second by giving you more from their Trade mission ability. A very useful Policy for the middle and late game.
*Mercenary Army - Allows purchasing of the Landsknecht unit, a very interesting unit which is useful for harassing the enemy, or for rushing a neighboring civilization due to their inexpensiveness (220 , but only after you've researched the Civil Service technology) and their ability to move immediately after being purchased. If you're not very offensively-oriented, it's only a bridge to a much more useful Policy:
*Mercantilism - This mid-level Policy lowers all prices for purchasing stuff in cities and also grants  for each financial building! Awesome, get it NOW!
*Protectionism - A high-level Policy which boosts . To maximize its effect, try to get as many Luxuries as you can, although you should be trying that anyway.
The finishing bonus of this tree upgrades Trading Posts with an additional 1 potential. When combined with the Economics tech, they start providing +3 ! You should start filling your free terrain with them ASAP. Also, you now get to purchase Great Merchants with .  
==Exploration==
Exploration is a new tree introduced in Brave New World, which is designed primarily to enhance coastal cities and sea trade. Thus all civilizations with many coastal cities benefit greatly from it, regardless of their strategic goals. Still, seekers of a cultural victory can benefit greatly from this tree, both because of the Wonder unlocked and because of its finishing bonus. Like Commerce, it is available from the Medieval Era, and thus is great for a second or third Social Policy choice.
Conceptually, Exploration represents the traditions of the great maritime civilizations such as Spain and England, which exclusively develop sea travel, overseas exploration, and trade.
Unlocking the tree gives +1 to all naval units, and additional +1 sight for combat ships. Combine this with the similar effect of the Great Lighthouse to get the most mobile navy ever! For greatest effect, try developing Deep Ocean travel capabilities first; otherwise your navy will be constrained to coastal waters. It also unlocks the Louvre, which makes this tree also important for seekers of a cultural victory.
*Maritime Infrastructure - A great starting Policy, it boosts in all coastal cities. Take this first if you have no problems with your , otherwise go with...
*Naval Tradition - This basic Policy increases for coastal cities with sea buildings. Start building Lighthouses and Harbors, if you haven't already. 
*Navigation School - This mid-level Policy boosts performance and spawn rate for Great Admirals, and also gives you a free Admiral. A good stepping stone towards forming your Grand Armada.
*Merchant Navy - This powerful mid-level Policy grants you +1 production per each sea building. Again, the more coastal cities you have, the greater the effect.
*Treasure Fleets - Grants +4  from all Sea Trade routes. Not that exciting, especially compared to earlier Policies, but still useful. And of course, it completes the tree giving you access to the awesome finishing bonus.
The ability to see Hidden Antiquity Sites may not sound all that interesting, but it can be surprisingly useful. With this bonus active, you'll be able to see secret sites that other civilizations that haven't completed this tree can't see and thus can't use! Besides, since the last patch, they are the only sites that grant unique Artifact-like objects, which can be used in all these Great Work of Writing slots that usually remain empty at the end phase of the game. This is a major advantage for those seeking a cultural victory, so start producing Archaeologists and putting them to work as soon as you complete the tree. You also get to purchase Great Admirals with , thanks to which you can have multiple Admirals with the same fleet and finally use their Repair Fleet ability!
==Rationalism==
Rationalism is the last Cultural tree available during the Renaissance Era. It is designed to boost production in a variety of ways, and as such is a must for those attempting a science victory. It is also great as means of speeding up general tech development, but because it becomes available relatively late, developing it might interfere with the development of an Ideology. At this stage of the game, Policies cost quite a bit of and you should be prioritizing your Ideology; still, if you have no Ideology yet and you're in desperate need of speeding up your scientific research, consider taking 2-3 Policies from this tree (as per the first progression option, which is detailed below).
Historically Rationalism represents the great shift in cultural priorities in the Renaissance from generalized and idealized entities like State and God to the singular Human and his rational approach to the world. This caused a veritable historic revolution in society and is represented here through its greatest impact: scientific advancement.
The unlock bonus of the tree increases output for the empire while is positive - a great boon and a no-brainer. The Wonder unlocked is the Porcelain Tower, which is both a booster to your Great Scientist generation in that city and the utility of research agreements (plus a free Great Scientist). It makes a great combo with the bonus from Scientific Revolution.
You have the choice of taking two distinct paths through the tree: Secularism -> Free Thought -> Scientific Revolution for an immediate boost to output, or Humanism -> Sovereignty for a more long-term general benefit. Both are well separated, unlike other trees where the last Policy/Policies usually require (almost) all the rest.
*Secularism - Provides +2 production for each Specialist (regardless of its type). An awesome bonus, which you should take first at any rate, unless you really love producing Great Scientists. Also, leads to Sovereignty.
*Humanism - Boosts production of Great Scientists by 25%. Useful in the long term, and opens up the path to the more useful...
*Free Thought - The best Policy in the tree, it increases the University's  bonus +17%, to a total of 50%; also gives 1 to every Trading Post! This combo is always powerful, but especially so in cities with Jungle tiles: those can have Trading Posts in them, which now produce +3 per tile, further increased by their city's University! The result: a whopping increase in science!
*Sovereignty - This mid-level Policy gives you +1 production from science buildings. 'Nuff said.
*Scientific Revolution - The high-level Policy boosts gained from research agreements by +50%. Combine this with the Porcelain Tower's effect to get a total of 100% increase, then start making agreements with everyone and race through the tech tree!
The finishing bonus of Rationalism gives you a free Technology, which can be either extremely useful or practically useless, depending on the timing. Also, you get to purchase Great Scientists with , which is actually much more useful in the long term.
Category:Game concepts (Civ5)
Category:Strategy (Civ5)
Category:Social policies (Civ5)