How do i upgrade my warriors to swordsman?

[CivsCivsCivs]

K.. i learned iron working, and i have a road to iron inside my terriotry... and i put my warriors inside my terriotry but it wont upgrade..? y? help!!!!!!!!

 

[Turner]

You need to have barracks in each city that has a warrior to upgrade, and you need to have enough gold to afford it.

 

[The Last Conformist]

To clarify, the Warrior needs to be in the city with the barracks.