Cannot upgrade units

[craco]

I'm playing C3C in regent mode and cannot upgrade some ground units even if I meet all the requirements.

For exemple I cannot upgrade a warrior to swordsman in a city that has a barrack and access to iron and has the Iron working advance. Its the same for a horseman to knight with the Chivalry advance in a city with a barrack, iron and horses, but, in the same city I can upgrade a spearman to pikeman.

What's is the reason for this ?

[Kloreep]

I would guess you don't have more than about 30 gold in the bank? thus you would be able to afford Spear->Pike, but not the more expensive Warrior->Swordsman or Horse->Chivalry

[vmxa1]

The only other thing you need is movement left in the unit to upgrade. Be sure to look at the city view to see if those resources are in its stratigic box.

If you use mass upgrade you have to have enough cash for all units or none is done. The cost is 3 times the shields difference of those units.

[craco]

You're right, I have only 17 gold.

I'm having some difficulty in amassing gold since this is the first time I'm trying Regent mode instead of warlord. I'll probably have to declare war to the Civ who forced me into a 19 gold/turn for Civalry in the first place to break the extortion of gold.

Thanks for the answer, both of you

[Kloreep]

Try not to pay GPT to the AI if you can avoid it, as it values each GPT as less than 20, which is what you'll pay it unless you break the deal.

And be warned, breaking a per-turn agreement like that will have repercussions for the rest of the game. You likely won't be able to trade other civs GPT again.