Upgrading towns, cities, castles

[colin666]

I'm having problems with upgrading a few towns in my egypt campaign (ayyabids I think)

I have a fortress with 15k pop & it still can't upgrade to a citidel!
there are also some towns with 6k+ population like aqaba and some towns in the egypt area.
Why can't I upgrade these towns/castles?

[Darvist]

Citadel upgrades at 18k, City at 10k, large city at 20k, and huge city at 40k. Stick a general with high chivalry to get it up faster. Just be sure he doesn't have negative traits that counter it. Generals will get additional bonuses after being in a city long enough with some luck. Also health bonuses and trade increase POP growth.

[colin666]

ok thank you!

Also..do the mercenaries you can recruit depend on what faction you are?
I started a Makuria campaign & I couldn't recruit those babo camel archers in Smyra (the province south of Ajaba idk if its called smyra) when I could in my egypt campaign.

[Taneda Santôka]

Yea, I think it depends on religion. And it's Bado-something