Here's the state of the world in 1160 AD.
With six cities, all pretty strong thanks to the whip (no tundra or island backwaters), I pressed hard for early universities and Oxford. Also, Leader Three came now thanks to the Great Library + National Epic combo, as a Scientist, for an obvious and much-needed Academy in Timbuktu, jumping national research by a good 20% from 278 to 336.
You can also see that China had been getting hacked up a bit. Mao was losing a war (and his capital) to both Hatshepsut and Roosevelt. Hatty's the game leader, but she considers me +13 friendly with her thanks to sharing civics and religion, so it's fine with me if she grows a bit.
Hatty came asking for "help":
With China rapidly disappearing, I had no fear of Mao's units or diplomatic attitude, so accepted Hatty's request. (I'd declined twice before, hence that -2 modifier there.) After two turns of the phoniest war in history, Hatty finished taking out Mao by herself.
So more time passes. After Liberalism-Nationalism, I researched Printing Press, then Guilds-Banking-Economics, all in about 6 turns each. Oxford finished during that too (the hard way, without Stone), in 1328 AD. I was now ahead of every rival by six monopoly techs: Nationalism, Education, Liberalism, Printing Press, Banking, and Economics. And after one turn of self-research on Engineering so that somebody would take Guilds in trade for it, the only techs by which I trailed were junk ones (Calendar, Drama, Theology.)
And my GNP is humming right along. A compact Financial empire with well-grown cities always takes the economic lead. I can now bring this home pretty much any way I want, especially after this happens. All at the same time, the Taj Mahal completed, Economics completed for a free Great Merchant, and my fourth natural leader popped from Timbuktu as a Scientist. That led to this uncommon sight:
Double Golden Age!
And now THAT's how to leverage water tiles. Financial attribute + Colossus + Golden Age = liquid Towns, just add water.
Replaceable Parts came in quickly, and I made a Spiritual visit to Serfdom to get the Lumbermills built faster. With my cities large, the food cost of Slavery whipping was now pretty high, and I sure didn't want to reduce city population during the Golden Age. Next it was finally time to allow Calendar to expire Stonehenge, to get going on Astronomy for the Observatories.
Hatty asks for Guilds, and I hand it over. No sense quibbling with my best ally over a devalued tech.
Also, it was time to pick another friend. A steady stream of Confucian missionaries had made sure to keep Hatshepsut as my best buddy, but nobody else considered me at more than +2 or so. My other bordermate, Elizabeth, was thoroughly Buddhist (had it in every city including the holy one), so no chance on getting her to convert. Saladin also had two holy cities of his own for Judaism and Islam. But Rome looked to be a ripe target. He hadn't founded any religions, so just had a mishmash, adopting Judaism officially for the benefit of about two cities. Some more Confucian missionaries made that happen in short order.
Also as a result of that Confucian activity (in this game, the puzzle pieces always interlock), the Confucian shrine had powered up to +22 gold/turn. This gave Kumbi Saleh a bit of a dilemma.
It's got the Heroic Epic and one national wonder slot free. The Heroic Epic wants another good military wonder to go with that (West Point or Red Cross), but the Confucian shrine wants to be paired up with Wall Street, and finally the Ironworks also wants a high-hammer city to call home. Well, I could put off this decision for a while, but ultimately Wall Street had to go here. That kind of cash payoff is worth sacrificing the military synergy, since I'm not planning on any large-scale conquest.
The war horns sound as Saladin declares war on Elizabeth. Fine with me -- those are the two biggest potential military threats to me at the moment, so let them busy each other. Tokugawa also declared on Elizabeth shortly later.
Here's another overview shot at the end of the Golden Age:
Next tech beeline was Corporation for Wall Street, then Chemistry-Sci Method-Biology. I finally didn't mind expiring the Great Library -- the beakers were now a pittance, and the city had just produced Leader Five (a Scientist who went for my second Academy), with the next a long way off, so the GPPs weren't really important either. Biology did its usual thing with food (I'd had to farm the land pretty heavily for the tundra cities), boosting my cities from around size 14 to 18 over time.
And while doing that, my capital really ran out of things to build. Available were no wonders and only a few meaningless buildings (castle, colosseum, jail). So Timbuktu just kept training Confucian missionaries and sending them over to America, and Roosevelt eventually converted on his own as well.
After Biology, now what? Well, it's time to decide whether diplomacy or space is my preferred victory type. Unfortunately for diplomacy, I've made the "mistake" of buddying up to the #1 AI civ (Egypt) who would be my election opponent. I'd have to carry the votes of America and Rome, and conquer England to add votes to my own total.
Space also has a few problems, chief among which is the fact that my economy is just about maxed with these six cities. If I want to turn in a competitive space time, I'll need to expand the economy outwards some now. And England's a target as ripe and juicy as they come. They're right on my border, they're getting gassed by two other civs, they still lack Gunpowder while I can have Rifling in six turns, and they have a nice selection of resources that I lack (rice, dyes, spices, stone, horses, gems!)
So since either the diplo or space paths are going to involve conquering England, I set research to Rifling and begin that plan. I revolted to Theocracy (after flipping Liberalism to England for Theology). Bureaucracy still looked superior to Vassalage so I stayed with that.