I'm still playing my original attempt with Peter. Haven't had much time for it...
Not used to Large. It's quite a step up. I teched furiously early on, but the AIs are way faster than I expected. Got MT in 350 AD and Rifling in 860 AD. One AI has lost its 7-8 core cities around 1000 AD, and capped. That's where I'm at right now. Cossacks alone should take care of two more AI, but it looks like I'll need a mountain of siege a bit later to go after Washington, who's grown quite large and keeps spamming troops.
Are you planning to use Artillery or Canons?
Might be easier to just beeline to Fission, complete The Manhattan Project, beeline to Rocketry and build Tactical Nukes. Two Tactical Nuke hits on an enemy stack will almost always wipe out all units. When the enemy stack is in a City, a Paratrooper can land and take the City in the same turn (or just use Cavalry just outside the blast range). Otherwise, sufficient Cavalry will take a City easily after a single Tactical Nuke, though you may need numerous Cavalry or the Blitz promotion to kill all surviving units. Of course, Gunships or Armor can do mop up too. One must offset the Tactical Nuke aim to allow mounted units or Armor to Blitz without being subjected to the blast.
I've started four Games so far:
1 Gilgamesh, Vulture Game, abandoned
1 Justinian I, Cataphract Game, marginal start
2 Julius, Praetorian Game, marginal starts
2 Julius, Praetorian Game, good starts
In my current Game, I'm at turn 110 (125 BC), and finally got the War Machine cranking out mainly Catapults and a few replacement Praetorians. I'm less than 10 from completing Engineering and will start building Trebuchets; beating down Longbowmen with Catapults can be expensive. I'm keeping my Economy from collapsing via good Technology trades where the AI usually provides only Wealth. I believe that building Cottages from the start may be the best way to a healthy Economy.
My first victim was Pacal II. I was quite surprised when five AIs followed my lead in attacking Pacal II. In all my previous Games, 2-3 AIs would attack me immediately after my first attack.
I believe I've been delaying my first attack too long. However, it seems more beneficial to spam Settlers (initial Cities) than spam Praetorians. Games where I've delayed attacking until I've built a few Catapults are going much better than when I proceeded without Catapults; Enemy culture grows too fast at Normal speed, especially compared to Marathon speed.
Sun Tzu Wu