One obstacle was war weariness - now up as high as +8 angry per city! And I can't end it, I must keep all my wars active. My final plan is to beat as many AIs as I can into submissiveness, then take capitulation from all of them simultaneously to slingshot past the domination limit.
So I put a click on the culture slider, and started whipping some Theaters... which was a mistake. I don't CARE if the population is angry, as long as all the food tiles are being worked, and they are. Angry population counts just fine towards score. That set me back about 30k in score, which would take some time to regrow.
If I can HAVE time. I actually had to intentionally give up a city (let it get recaptured, then raze it) to stay under the domination limit. I strongly considered just ending this now (soon as Saladin would cap) and taking my 1,000,000 points. Yes, I'm deep into a milking phase, exactly what I wanted to avoid. But no, I've gotta push this as far as it can go. This is a one time shot. I am most certainly not doing this again. And I'm already 30 hours in, what's another 10 of milking. The score has to stop increasing soon, right? Right?
The Taj Mahal golden age came, giving me a free civics change. I'd stopped building units in favor of happiness buildings, now with ample units to finish all the killing, armies of about 12 cannons each on four or five different fronts. So Vassalage can go in favor of Nationhood (could use the barracks happy, and EP for stealing), Theocracy in favor of Free Religion (more happy), and Police State since I don't care about Rep research now.
So I beat down Joao to the point of capitulating, then Saladin, along with Sitting Bull with a separate army, who went on to Bismarck, and another army for Gilgamesh, while the first army also hit Mehmed and Willem. No AI even got to Gunpowder, so I had cannons against longbows and something like a 10:1 kill ratio all around.
As I geared up for the vassal flourish finish, a minor set of problems happened. Gilgamesh said he could not vassalize because "joining the war on your side is not possible for us." Huh? I haven't seen that before - what the heck happened? Willem and Gilgy just signed a peace treaty, so Gilgy cannot declare again on Willem. Same happened between Willem and Ragnar. I thought to work around this by signing non-capitulation peace with Willem, and take everybody else as vassals to end the game, but that wasn't available because I had not attacked Portugal for a while and he had climbed out of capitulation.
I had to make peace with Gilgy myself, just in order to give up another city and stay under domination. I waited 10 turns - fortunately with my score still climbing by a couple thousand per turn - and declared again. This time things went as planned, and I took seven vassal capitulations on the same turn to rocket over the top. That added another 1000 points of base score, over 250,000 of normalized score.
(There was another peace deal between Ragnar and Bull which meant I could take only one of them as a vassal. I was in position to capture a city from Bull, so did that, signed peace with him, and capped Ragnar. Almost a perfect slate of vassalage; Pacal is an island colony of no import.)
Other details that got finished off over the last several turns: Liberalism to Medicine, just for the tech points. Build Sid's Sushi, just for the wonder points. (It's only +6 food, not worth milking for population growth.) Run some EP to steal the remaining AI techs of Theology, Divine Right, Astronomy.
Domination Victory in 740 AD.
AND THE HIGHEST SCORE IN REALMS BEYOND HISTORY