To be sure it happened in time, I ran culture in Pi-Ramesses to get the Cow, which we did two turns later. In 475AD Gunpowder is researched, and Cuirs are lined up almost everywhere. Some infra is still needed in a few cities.
I waited a few turns extra to be able to whip some infra with nice OR-overflow, but in 520AD we go Theo for (often) an extra promotion. Unfortunately the missionary failed on the island, but otherwise we have Buddhism everywhere. In the same turn, both Isabella and Gilgamesh became friendly. Though it went a bit back and forth for the whole turnset. I traded a bit, which not all of them liked. But we got our hands on Printing Press, Optics and Drama, which was nice, and much later Guilds.
Saladin has built up a sizeable stack in the east near Giza, and he just got Guilds.
As you see in that image, a couple workers have roaded for him, and with 20 Cuirs I figured it was time to release them. Hopefully he would invade and not upgrade. I removed the warrior MP and left the city empty, so Saladin wouldn't get any crazy ideas.
Had parked some Cuirs within reach of both Bagdad and Basra. He kept sending units around, so wasn't sure where I needed them most.
The start goes well.
Meanwhile Saladin invades with his stack, thankfully without any naughty upgrades. Feels very unsafe over there, but we'll try to deal with it.
We attacked with what was possible, removed most catas in the process and some maces and HAs. He did remove most of the defence before the walls came up. Then threw all he had at us, which was a bit surprising tbh.
Normally I'd probably have gotten out some Longbows for protection, but err... we can't. Lacking Hunting and Archery
Throughout I've been whipping mercilessly. Even did the capital once. The HE city has been left alone, because I want it to pump out units for future wars. It's not very strong on hammers tbh, but it's enough. If I get that far, it can start to get workshops when they don't suck any more.
After losing that stack and some more cities, including Medina with the shrine, he's hurting pretty bad and is willing to give us Guilds for peace. We keep pushing. I probably overdo it a bit, and wind up risking the super medic to take a city as we move closer to size 18 Mecca.
Around now he was willing to capitulate. However, being that close to such a juicy city, it felt wrong to stop. Fostat fell further east. Mecca took longer than I hoped due to heavy reinforcements, but we got it eventually.
Naturally he was willing to cap now, but the default offer was a size 7 city Aden (which we besieged heavily), but not Banking. I sniped what we could reach, busted some tiles, and tried to swap out Aden for Banking. He agreed, and becomes a vassal. I also asked him ever so nicely to swap to Buddhism. Suddenly Isabella loves him. It may not be realistic, perhaps she is too strong, or soon will be, but it would have been cool to peace vassal Isabella. Sadly she fell down to +9 Pleased, but there is still room for improvement from religion and civic. If it happens soon enough, we can get RepParts from her too.
Cuirs are running rampant here, but this is an overview of the expanded Egyptian empire.
Although it was terribly expensive at 230

a piece, I did decide to upgrade some WCs. A few were well-promoted and one or two were for better city defence in risky situations.
edit: Almost forgot, I forced Marble out of Saladin and started on Taj Mahal. I'm sure somebody else will beat me, but hopefully we can get a decent chunk of failgold out of it. For some odd reason Isabella didn't spend her GE on Taj. Weird. Maybe she had started on it elsewhere and therefore went for something else..?
Also, for the first time in probably thousands of years, Thebes has taken back the second corn. Woot!
Where do we go from here? I'm thinking Wang next, although it's a little awkward due to the jungle and suchlike (I gifted him Muscat btw, which made him Pleased). Isabella is the natural target really, but she's close to Conquistadors and it would have been very useful to get her as peace vassal. May not be possible though, especially once she gets Conqs and mass upgrade the lot.