I felt the next step was to prepare for war against Egypt, my neighbor. Since I had poured a large number of shields into wonders (something I like doing even if I know it isn't quite worthwhile), this wasn't an option before. I never built a single Gallic Sword all game, actually.
In AD 400 I take advantage of a 2-for-1 deal on Education and Gunpowder. I don't have any saltpeter, but it looks like England has tons, and I don't intend to build many muskets or declare war soon, as it'll take a while to build up a decent number of trebuchets and knights that I'll be upgrading to cavalry for the eventually war.
During this trade I use a trick that I don't see often in RBCiv games or SG's, so let me mention it ... if an AI cannot quite offer market value for a tech I am selling, I often simply give the AI money, which I will get back anyway once I sell the tech. I'm not 100% sure of this, but I do think this greatly reduces the chance that the AI will demand something (which is annoying if it's a lux, resource, or tech rather than the usual 25-50g). Later in the game, it can be profitable to give an AI enough money so that it has 1000g. This will often cause the AI to magically have more gpt available from Wall Street; a tech sale will then not only get my 1000g back, but up to 50gpt extra.
For now, though, this trick just gets me up in Carthage's good graces.
I begin construction of non-cutout defenses and some knights and trebuchets. Egypt's Memphis completes Copernicus's Observatory
in AD 510. Ah, another wonder I can capture.
In AD 520 I pull off this succession of tech deals:
Wines + WM + 1003g to Egypt for WM + Astronomy
Furs + 269g + Astronomy @mono to Portugal for Chemistry
Chemistry @mono to Egypt for Navigation
+ Music Theory
a whole bunch of money-making map deals now that I have the ability to trade maps
Give 200g to Carthage, then trade Chemistry + Navigation to Carthage for Banking
+ WM + my 200g back
Astronomy then goes to England for Dyes + 6gpt
That's a 5-for-1 deal. Quite the bargain.
I then swap Gergovia to Magellan and Lugdunum to Bach.
AD 590 sees the first war action all game, as Portugal declares war on Rome. Rome doesn't have much territory, so I'm figuring Portugal will do well here. The peaceful AI's have been researching quickly, perhaps a shade too fast even though I'm aiming for a space win.
In AD 640 a 2-for-1 deal on Economics and Metallurgy appears, and I take it. Augustodurum by now is a powerhouse, even though it has not a single grass or plains tile; the deserts and hills are enough for it to make a lot of shields in this variant. It swaps to Bach as I swap my Bach build to Smith -- with happiness already not much of an issue with Sistine-powered cathedrals, it's better to get Smith if I have a competition problem.
Roman cities fall quickly before the Portuguese as Gergovia completes Magellan's Voyage
in AD 700.
In AD 730 Egypt declares war on Carthage. I'm nearly ready for war now, so this is very convenient. I'll wait a few turns for Egypt's units to wander into Carthage or get killed, then start my own war.
In AD 750 I get Physics and Printing Press in a 2-for-1 deal. Here is the state of my empire, which is almost ready for its first war: