I played 2 turns, and stopped to get input before a strategic decision.
(0) 1200 AD: Everything looks okay.
(1) 1210 AD: Cathy takes out our two Swords by Rostov. She also attacks in the south, defeating an Ax and LB, and losing an Elephant. She now has a CB on the Forest next to the Iron and Bantu.
If we don't evict the CB on the Forest (odds not good for any of our units), she will move her stack there and we won't be able to knock her off (not to mention defend the Iron and Bantu at the same time). If it takes 2 or more units to kill the CB, her stack could very well decimate ours. So I go all out on attack and get some excellent rolls:
Pike beats Spear
Horse Archer loses to CB
Cat beats CB (9% odds

)
CB beats Horse Archer
Ax beats Sword
Ax loses to Ax
Horse Archer beats CB
Cat withdraws
Sword beats Sword
Pike beats Spear
(7-2)
She is left with 4 units, 3 of which are at 0.7, 0.5, and 0.4 health. We have 5 units at full or near full, 2 moderately wounded, and 3 very wounded

with a Pike in Bantu next turn.
(2) 1220 AD: A Sword beats a Horse Archer, and a new Horse Archer appears. The rest of her units retreat toward Rostov. One of our Pikes kills HA.
Here's the strategy part:
Hatty will give us Civil Service for Guilds--I think that's a no-brainer. Izzy will declare on Cathy for Music. Mansa's got nothing for a reasonable price.
Case for continuing war:
--We just handed it to them near Bantu.
--Izzy will join for cheap.
--We are 3rd in production, so although we are a bit gassed now we are not in danger of getting overrun.
Case for ending war:
--Izzy is last in score, so we bring her in at a risk.
--Our northern forces amount to a Sword and two Cats. Cathy appears to be building up a stack in Rostov; if she gets it out quick, she could walk to MadV (2 Archers atm).
(Not much now, but the Sword next to it and the three wounded units on the way make it much more potent.)
--It will take a while to get Knights and Maces out, and until then I don't think we can take any cities. Really the only cities we could attack are Rostov and Vladivostak (the next closest is St. Pete, 6 tiles away and her holy city). Rostov can't be done now, and while we could probably get Vlad it's such a miserable city I don't think it'll be worth it.
She's not talking to us, so we've got at least another turn, but I think if it were up to me I would make peace as soon as possible, build Knights and Maces, set up a northern stack, declare (possibly with Izzy, if she's still cheap) and go for Rostov in ten turns. But I think we all want to expand and I could be persuaded the other way.