Well, the first thing to do in a war like this is to go shopping at the help store. It was lightly but adequately stocked: Peter and Frederick both joined me for some techs.
Peter shares a long border with Rome so should divert a good chunk of Rome's forces away from me. Frederick isn't so great logistically, being on my opposite side from Rome, but any help is still appreciated. And this should also cement diplomatic relations with Frederick.
I also sold cheap techs (Priesthood, Alphabet) around to get everybody's spare cash, totalling 800, to upgrade some warriors to axemen. And I set Research to 100% on Construction, due in 7 turns, in order to get catapults.
Rome turned out to be quite the paper tiger. His entire offense consisted of a stack of two axemen, and later two lone Praetorians. I easily held off all of them; the Praetorians suicided against my axemen defending in jungles.
And I easily captured two cities defended by only two archers each. These two city captures were important, since they would get me to the all-important total of nine cities, to be able to build nine of each religious temple to qualify for three cathedrals.
Rome signed peace after the two city captures. I could easily have wiped him out, but that's a no-no by the scenario rules. We need to keep Caesar alive so we can shoot him into space to watch our movies. Or something like that.
And here's a good overview shot from a few turns later.
I'm finally assigning specialization roles to the cities. First job is to pick the three cultural cities. Ottawa as the capital, with culture from the Parthenon, is a no-brainer. And with loads of food, it's being groomed as an eventual Great Artist farm there with the National Epic. And Toronto is clearly the best site after the capital.
The third cultural city is a tough call between Montreal or Vancouver. Vancouver is a stronger site, but Montreal has a head start with the Great Lighthouse. In the interest of overall civ strength, I went with Montreal, while Vancouver gets the Heroic Epic. With five hills, food to support them, horses, and lots of watermillable tiles, Vancouver could be a supremely strong military producer.
Edmonton also has a useful niche: it's training all my Missionaries to spread the religions around. It got done with its basic buildings (granary, library) quite early, so it doesn't have anything more pressing at the moment. Winnipeg and Phrygian have been slow starters and late to receive worker labor, but will also be solid producers.
Also I had just crammed in Yellowknife up there, on Stone. In most games I wouldn't bother, but we want Stone bigtime here, because Jewish Synagogues use Stone. It'll help the Hanging Gardens too, and also an attempt at Chichen Itza next for the scenario points. Finally, the city snags fish too.
By the way, the Parthenon is a culture powerhouse. I'd written off that iron and ivory west of my capital, but the city just reached out and glommed those tiles.
Oops.
Neapolis, that I'd captured from Rome, flipped away from me to Russia! First time I've ever had a flip away from me in Civ 4.
And if I might rant for a bit, here's a GREAT example of the big flaw in the Civ 4 culture flip system. It's too dependent on only the cultural influence in the city tile. If I had razed Neapolis and replaced it one tile north or west, it would've been outside Russian cultural reach and perfectly safe from a flip. One tile should not make 100% difference in an eventual flip chance! The flip chance should depend on the relative cultural influences within the entire fat cross. Or a nation's cultural influence should gradually diminish with distance instead of dropping dead right at the border. 
Civ 3 actually had that right to some extent, though it was a little too easily abusable.
Toronto went for the Hanging Gardens for the culture and for the wonder's effect, both fairly helpful here. The Hanging Gardens is just a no-brainer to build with Stone and even often without. It pays back more than its hammer cost via whipping fodder, and the health is just gravy, and Great Engineer points are always welcome.
Next it also got Chichen Itza, just for the scenario points. Hey, we've got Stone and the Industrious trait, let's use them!
My second Great Person would still be a Merchant from the Great Lighthouse. I'd been sort-of planning to use him to slingshot Civil Service anyway, but my normal research got there long before the GP arrived. I revolted to Bureaucracy of course, and traded Civil Service for Feudalism and Metal Casting, and belatedly realized that we get cheap forges that we should've been building much earlier.
And halfway through researching Education, I realized that Notre Dame would be a nice cultural prize and cheap with Stone, so made a sidetrack research to Music. Do I have enough production bonuses on the wonder here? 
Unfortunately I forgot to make any attempt at the actual best wonder for a cultural victory - the Sistine Chapel. I didn't have Theology so it never came up as a build item, and I just forgot about it until Saladin got it. Well, it's in Mecca, right on my border, so it could be a conquest target later. For now, though, we share a religion with Saladin, and we're more concerned with keeping our friends and building cultural items before 1502 AD.
And with Paper, I traded to fill in the rest of the map that I hadn't scouted. Here's an overview shot with everybody.
