Pre-turn
Sell Chemistry to Caesar for all his gold: 38 gp + 7 gpt (little money, but better in our pockets than in another AI's).
Aztecs and Mongols are up Navigation, Physics and Metallurgy.
Vikings and Zulus are up Navigation and Metallurgy.

Our military advisor says that the Aztec army has Cavalry units.
Engage in some map trading with the known civs.
Press Enter
The Vikings discover Free Artistry and start Shakespeare.
Turn 1 - 1010 AD
The AIs are no more than two techs from the Industrial Age, and we are starting to fall behind badly; no matter how many Medieval Infantry and Pikemen we build, it will be game over as soon as they begin arriving with Cavalries and Riflemen.
There is another reason why we need to catch up in tech: if we cannot start wars between AIs, they will keep on researching and trading techs the way they have been doing, and we won't have a chance to slow down the tech pace.
The best way to do that that I can think of right now, is to stay one-two techs ahead of them and keep them broke by judicious selling of those techs.
Our only chance to catch up now is to take advantage of the passing of age and of our scientific trait. So, I set research on Economics to the maximum sustainable level (that is, deficit research without going negative with the treasury).
Move some units around.
Turn 2 - 1020 AD
I think we can still squeeze at least three more cities in the jungle area and in the forsaken lands between Larsa and Ashur. Three cities will mean at least 45 culture points per turn after rushing some buildings... So I set Ashur back to Settler.
Turn 3 - 1030 AD
Rush Cathedral in Eridu
Turn 4 - 1040 AD
Rush University in Samarra
Turn 5 - 1050 AD
Larsa: Aqueduct - Marketplace (can also be switched to University)
Turn 6 - 1060 AD
Mongols have completed Magellan
Turn 7 - 1070 AD
Mongols reached the Industrial Age.
Aztecs started Smith!
Let's hope it isn't too late. We simply haven't got enough gpt to afford buying all those techs.
Incidentally, wasn't it unlucky that the Vikings researched Free Artistry, the Mongols ToG and the Aztecs Economics in parallel...
Luckily, the Aztecs haven't sold Economics to anyone.
Start some trading:
Sell Democracy to Rome for 26 gp + 3 gpt (all they have)
Sell Economics to Vikings for Free Artistry and 22 gp
Sell Economics + Free Artistry + 122 gp + 45 gpt to Zulus for Physics and Metallurgy
Sell Economics + 41 gpt to Mongols for Magnetism
Sell Magnetism to Zulus for 30 gpt + 39 gp
There is no way to buy Theory of Gravity at monopoly price from Temujin. Luckily, a havy gpt deal we have with them is expiring in three turns, which will allow us either to speed up our own research on ToG, or to buy it directly.
I set research at zero for these turns.
Yuk. In all this mess I hadn't noticed that we got a Scientific Leader! The first one I ever see

I switch the prebuild in Nineveh to Shakespeare, due in nine turns.
I leave the leader alone, for the moment.
Rush university in Telloh.
Turn 8 - 1080 AD
Vikings reach IA too. This may actually help us, lowering the cost of ToG.
Found New Nineveh - Temple
Turn 9 - 1090 AD
Rush University in Akkad
Our culture is 14794
Turn 10 - 1100 AD
The gpt deal we had been paying to Mongols expires.
So ends our trading round started in 1070 AD (I know, it's my last turn, but I had been waiting so eagerly for this...

):
We can now buy Theory of Gravity for merely Ivory, Dyes, WM, 66 gp and 51 gpt.
We get Nationalism as our free tech.
Sell Nationalism to Mongols for Military Tradition, Navigation, WM, 86 gp, 154 gpt (all they have)
Sell Nationalism to Vikings for Horses

WM, 78 gp, 101 gpt
There is another deal we may make with Zulus: they have Saltpeter to sell, and we could buy it for ToG and money, or that + money for ToG + Nationalism.
I don't know about this one -we may want to build a few horses and then upgrade, or buy Saltpeter and go straight for Cavalries. Team's call.
We are now on tech par with everyone, and making 300+ gpt at zero science.
And everyone else is broke (except the Zulus, that are making around 30ish gpt).
Our culture: 15067 (273 cpt from last turn)
Two settlers are being produced, and I had these locations in mind for them, but that's of course subject to collective agreement.
Notes
- I set research to Medicine, but as we started this turn we can change to Steam Power freely. I also left the slider at 0% science -we may want to raise it to reach Scientific Method first.
- I haven't made any deal with the Zulus, but we may want to get that saltpeter.
- I haven't done anything with the leader. There are three wonders available at the moment -Shakespeare, Adam Smith and Newton. We can probably build Shakespeare first (it is only six turns away), and then choose one of the remaining two. The third one will be lost in the cascade.
I didn't rush anything with the leader just because of the cascade risk -my idea was to wait for Shakespeare to be ready and use the leader on the same turn.
- For our military, I would mainly build Trebuchets/cannons and horses/cavalries. If we upgrade our Pikemen, we probably won't need to build more defensive units. In this sense, the build orders in some of our cities will have to be reviewed: I have left some Aqueducts and Marketplaces around that may be changed, and in the confusion of all this trading I have probably overlooked some builds.
-- Here is the save --